diff --git a/script.js b/script.js
index bbe8a293..91df66fa 100644
--- a/script.js
+++ b/script.js
@@ -1,4 +1,349 @@
+// Blackjack Base Game Walkthrough
+// 1. playable game with minimum functions: creating deck, shuffling, dealing cards, evaluating winner
+// 2. ability for the player to hit or stand
+// 3. ability for the dealer to hit or stand
+// 4. variable value of Ace - either '1' or '11'.
+
+// ===== ===== Pseudocode for Version 1 ===== ===== //
+// 1. define player and dealer
+// 2. create and shuffle a game deck
+// 3. draw 2 cards for player and dealer respectively
+// 4. win conditions
+//      -- blackjack
+//      -- higher hand value
+// 5. display hands of both player and dealer and declare winner
+
+// ==== ==== Pseudocode for Version 2 ==== ==== //
+// 1. extra game mode "hit or stand"
+// 2. functionality for user to input hit or stand.
+
+// ===== ===== Pseudocode for Version 3 ===== ===== //
+// 1. Dear to hit or stand ONLY AFTER player choose to stand
+// 2. if dealer hand value is less than 17, dealer hits
+// 3. if dealer hand value is more than 17, dealer stands
+
+// ===== ===== Pseudocode for Version 4 ===== ===== //
+// if totalHandValue, including an ace, is less than 21, ace value is 11
+// when totalHandValue, including an ace, is more than 21, ace value is reduced to 1.
+
+/* ================================================== */
+/* =========== GLOBAL VARIABLES ======================= */
+/* ================================================== */
+
+// Declare game modes
+var GAME_START = "game start";
+var GAME_CARDS_DRAWN = "cards drawn";
+var GAME_RESULTS_SHOWN = "results shown";
+var GAME_HIT_OR_STAND = "hit or stand";
+var currentGameMode = GAME_START;
+
+// Declare variables to store player and dealer hands
+// We use arrays as each hand will be holding multiple card objects
+var playerHand = [];
+var dealerHand = [];
+
+// Declare variable to hold deck of cards
+var gameDeck = "empty at the start";
+
+/* ================================================== */
+/* =========== DECK CREATION FUNCTIONS ============== */
+/* ================================================== */
+
+// Function that creates a deck of cards, used by createNewDeck function
+var createDeck = function () {
+  // deck array
+  var deck = [];
+  // for 'while loop' to create suits for cards
+  var suits = ["Diamonds", "Clubs", "Hearts", "Spades"];
+  var indexSuits = 0;
+  while (indexSuits < suits.length) {
+    var currSuit = suits[indexSuits];
+    // 13 ranks... ace to king - rank to define "card positions"
+    var indexRanks = 1;
+    while (indexRanks <= 13) {
+      var cardName = indexRanks;
+      // define card value - differentiate from rank: 'ace' = 1 / 11, 'jack' & 'queen' & 'king' = 10
+      if (cardName == 1) {
+        cardName = "ace";
+        // define ace value as 11 all the way. if handValue > 10, -11 to total value
+        // vs. coding a function to redefine the value for ace
+      }
+      if (cardName == 11) {
+        cardName = "jack";
+      }
+      if (cardName == 12) {
+        cardName = "queen";
+      }
+      if (cardName == 13) {
+        cardName = "king";
+      }
+      var card = {
+        name: cardName,
+        suit: currSuit,
+        rank: indexRanks,
+      };
+      deck.push(card);
+      indexRanks = indexRanks + 1;
+    }
+    indexSuits = indexSuits + 1;
+  }
+  return deck;
+};
+
+// Function that generates a random number, used by shuffle deck function
+var getRandomIndex = function (size) {
+  return Math.floor(Math.random() * size);
+};
+
+// Function that shuffles a deck, used by createNewDeck function
+var shuffleDeck = function (cards) {
+  var index = 0;
+  while (index < cards.length) {
+    var randomIndex = getRandomIndex(cards.length);
+    var currentItem = cards[index];
+    var randomItem = cards[randomIndex];
+    cards[index] = randomItem;
+    cards[randomIndex] = currentItem;
+    index = index + 1;
+  }
+  return cards;
+};
+
+// Function that creates and shuffles a deck
+var createNewDeck = function () {
+  var newDeck = createDeck();
+  var shuffledDeck = shuffleDeck(newDeck);
+  return shuffledDeck;
+};
+
+// Function that checks a hand for blackjack
+var checkForBlackjack = function (handArray) {
+  // Check player hand
+  var playerCardOne = handArray[0];
+  var playerCardTwo = handArray[1];
+  var isBlackjack = false;
+
+  // if there is a blackjack, return true
+  // possible scenarios:
+  // 1st card ace, 2nd card 10 or picture cards
+  // 1st card 10 or picture cards, 2nd card, ace
+  if (
+    (playerCardOne.name == "ace" && playerCardTwo.rank >= 10) ||
+    (playerCardOne.rank >= 10 && playerCardTwo.name == "ace")
+  ) {
+    isBlackjack = true;
+  }
+
+  // else return false - don't need statement because variable already set to false
+  return isBlackjack;
+};
+
+/* ================================================== */
+/* =========== GAME FUNCTIONS ======================= */
+/* ================================================== */
+
+// Function that calculates a hand
+var calculateTotalHandValue = function (handArray) {
+  var totalHandValue = 0;
+  var aceCounter = 0;
+
+  // loop through player or dealer hand and add up the values
+  var index = 0;
+  while (index < handArray.length) {
+    var currentCard = handArray[index];
+
+    // for jack, queen, king, value is 10
+    if (
+      currentCard.name == "jack" ||
+      currentCard.name == "queen" ||
+      currentCard.name == "king"
+    ) {
+      totalHandValue = totalHandValue + 10;
+    } else if (currentCard.name == "ace") {
+      totalHandValue = totalHandValue + 11;
+      aceCounter = aceCounter + 1;
+    } else {
+      totalHandValue = totalHandValue + currentCard.rank;
+    }
+    index = index + 1;
+  }
+
+  index = 0;
+  while (index < aceCounter) {
+    if (totalHandValue > 21) {
+      totalHandValue = totalHandValue - 10;
+    }
+    index = index + 1;
+  }
+  return totalHandValue;
+};
+
+// Function that displays the player and dealer hands in a message
+var displayPlayerAndDealers = function (playerHandArray, dealerHandArray) {
+  // Player hand
+  var playerMessage = "Player Hand: <br>";
+  var index = 0;
+  while (index < playerHandArray.length) {
+    playerMessage =
+      playerMessage +
+      "- " +
+      playerHandArray[index].name +
+      " of " +
+      playerHandArray[index].suit +
+      "<br>";
+    index = index + 1;
+  }
+
+  // Dealer hand
+  index = 0;
+  var dealerMessage = "Dealer Hand: <br>";
+  while (index < dealerHandArray.length) {
+    dealerMessage =
+      dealerMessage +
+      "- " +
+      dealerHandArray[index].name +
+      " of " +
+      dealerHandArray[index].suit +
+      "<br>";
+    index = index + 1;
+  }
+
+  return playerMessage + "<br>" + dealerMessage;
+};
+
+// Function that displays the total hand values of the player and the dealer in a message
+var displayHandTotalValues = function (playerHandValue, dealerHandValue) {
+  var totalHandValueMessage = "<br>Player total hand value: " + playerHandValue;
+  return totalHandValueMessage;
+};
+/* ================================================== */
+/* =========== MAIN FUNCTIONS ======================= */
+/* ================================================== */
+
 var main = function (input) {
-  var myOutputValue = 'hello world';
-  return myOutputValue;
+  var outputMessage = "";
+
+  // FIRST CLICK
+  if (currentGameMode == GAME_START) {
+    // Create the game deck
+    gameDeck = createNewDeck();
+
+    // Deal 2 cards to player and dealer respectively
+    playerHand.push(gameDeck.pop());
+    playerHand.push(gameDeck.pop());
+    dealerHand.push(gameDeck.pop());
+    dealerHand.push(gameDeck.pop());
+
+    // check player and dealer cards
+    console.log("player hand ==> ");
+    console.log(playerHand);
+    console.log("dealer hand ==>");
+    console.log(dealerHand);
+
+    // progress the gameMode
+    currentGameMode = GAME_CARDS_DRAWN;
+
+    // write and retrun the appropriate output message
+    outputMessage =
+      'Everyone has been dealt a card. Click "submit button to evaluate cards!';
+
+    return outputMessage;
+  }
+
+  // SECOND CLICK
+  if (currentGameMode == GAME_CARDS_DRAWN) {
+    // check for blackjack
+    var playerHasBlackjack = checkForBlackjack(playerHand);
+    var dealerHasBlackjack = checkForBlackjack(dealerHand);
+
+    // console.log("Does Player have Black Jack? ==>", playerHasBlackjack);
+    // console.log("Does Dealer have Black Jack? ==>", dealerHasBlackjack);
+
+    // Condition when either player or dealer has black jack
+    if (playerHasBlackjack == true || dealerHasBlackjack == true) {
+      // both player and dealer has blackjack -> tie
+      if (playerHasBlackjack == true && dealerHasBlackjack == true) {
+        outputMessage = "It is a blackjack tie!";
+      }
+      // only player has blackjack -> player wins
+      else if (playerHasBlackjack == true && dealerHasBlackjack == false) {
+        outputMessage = "Player wins by blackjack!";
+      }
+      // only dealer has blackjack -> dealer wins
+      else {
+        outputMessage = "Dealer wins by blackjack";
+      }
+    } else {
+      outputMessage = "There is no blackjack!";
+
+      // change game mode
+      currentGameMode = GAME_HIT_OR_STAND;
+    }
+
+    // appropriate output message
+    return outputMessage;
+  }
+
+  // HIT OR STAND
+  if (currentGameMode == GAME_HIT_OR_STAND) {
+    // Player Hit
+    if (input == "hit") {
+      playerHand.push(gameDeck.pop());
+      outputMessage =
+        displayPlayerAndDealers(playerHand, dealerHand) +
+        '<br> You drew another card. <br>Please input "hit" or "stand".';
+    }
+
+    // Player Stand
+    else if (input == "stand") {
+      // calculate the total hand value of both player and dealer
+      var playerHandTotalValue = calculateTotalHandValue(playerHand);
+      var dealerHandTotalValue = calculateTotalHandValue(dealerHand);
+
+      while (dealerHandTotalValue < 17) {
+        dealerHand.push(gameDeck.pop());
+        dealerHandTotalValue = calculateTotalHandValue(dealerHand);
+      }
+
+      // compare total hand value
+      // same value -> tie
+      if (playerHandTotalValue == dealerHandTotalValue) {
+        outputMessage =
+          displayPlayerAndDealers(playerHand, dealerHand) +
+          "It is a tie!" +
+          displayHandTotalValues(playerHandTotalValue, dealerHandTotalValue);
+      }
+      // player higher value -> player wins
+      else if (playerHandTotalValue > dealerHandTotalValue) {
+        outputMessage =
+          displayPlayerAndDealers(playerHand, dealerHand) +
+          "Player wins!" +
+          displayHandTotalValues(playerHandTotalValue, dealerHandTotalValue);
+      }
+
+      // dealer higher value -> dealer wins
+      else {
+        outputMessage =
+          displayPlayerAndDealers(playerHand, dealerHand) +
+          "Dealer wins!" +
+          displayHandTotalValues(playerHandTotalValue, dealerHandTotalValue);
+      }
+    }
+    // Input validation
+    else {
+      outputMessage =
+        'Wrong input... only "hit" or "stand" are valid. <br><br>' +
+        displayPlayerAndDealers(playerHand, dealerHand);
+    }
+
+    return outputMessage;
+  }
 };
+
+// calculate the total hand value of both player and dealer
+// compare total hand value
+// same value -> tie
+// player higher value -> player wins
+// dealer higher value -> dealer wins
+// change game mode
+// appropriate output messag