add new page about node selection process

website/docs/reference/node-selection/node-selection.md

@@ -0,0 +1,82 @@
+---
+title: "Node selection"
+description: "Learn how to select and exclude resources in dbt."
+sidebar_label: "About node selection"
+---
+
+This page outlines the steps dbt follows when selecting resources. To understand dbt resource selection:
+
+- Think of `--select` and `--exclude` as two filtering steps applied sequentially.
+- Recognize that the type of command determines the final resources executed.
+- Understand that edge cases like `dbt test` or `source:` aren't exceptions but logical outcomes of this schematic.
+
+### Resource selection
+
+dbt selects any resource that matches one or more `--models` or `--select` criteria in the order of:
+
+- Selection methods: Methods like `tag:`, `source:`, `model:`.
+- Graph operators: Operators like `+` (which selects upstream/downstream dependencies).
+- Set operators: Combining resources with `,` or other logical operators.
+- Selected resources may include:
+  - models
+  - sources
+  - seeds
+  - snapshots
+  - 
+  - tests
+
+### Applying --exclude criteria
+
+dbt removes any resource that matches one or more `--exclude` criteria. If the command is `dbt test`, dbt also de-selects any test that directly depends on an excluded resource.
+
+### Resource filtering by command type
+
+After applying selection and exclusion rules, dbt retains only the resources relevant to the current command:
+
+- `dbt run`: Keeps models.
+- `dbt seed`: Keeps seeds.
+- `dbt test`: Keeps tests (and selects tests that depend on selected resources).
+- Other commands: Filters resources specific to the actual command.
+
+### Examples of resource selection
+
+The following examples show how dbt selects resources based on the specific command and the `--select` and `--exclude` criteria.
+
+#### Example 1 
+Selecting a model and downstream dependencies:
+
+```bash
+dbt run -s my_model+
+```
+
+This command selects `my_model` and all downstream dependencies (`+`). It selects only models because `dbt run` filters out other resource types.
+
+#### Example 2
+Testing a model with its tests:
+
+```bash
+dbt test -s my_model
+```
+
+This command selects `my_model` and any tests directly associated with it. It filters out models, keeping only tests for execution.
+
+#### Example 3
+Excluding a resource:
+
+```bash
+dbt run -s my_model --exclude tag:deprecated
+```
+
+This selects `my_model` and all downstream dependencies. It excludes any resource tagged as `deprecated` and filters resources to retain only models (because `dbt run` is invoked).
+
+#### Example 4
+YAML selectors differ slightly:
+
+The `exclude:` key in YAML selectors supports more complex set logic, allowing fine-grained control over resource inclusion and exclusion.
+
+### Considerations
+Certain cases may seem inconsistent but follow the same selection process:
+
+- Tests that depend on excluded models are de-selected automatically in dbt test.
+- `source:` and `model:` selection methods behave differently.
+- Using `+` or `,` can feel unintuitive but works predictably based on graph structure.

website/docs/reference/node-selection/syntax.md

@@ -1,5 +1,6 @@
 ---
 title: "Syntax overview"
+sidebar_label: "Syntax overview"
 ---
 
 dbt's node selection syntax makes it possible to run only specific resources in a given invocation of dbt. This selection syntax is used for the following subcommands:

website/sidebars.js

@@ -1087,6 +1087,7 @@ const sidebarSettings = {
           type: "category",
           label: "Node selection",
           items: [
+            "reference/node-selection/node-selection",
             "reference/node-selection/syntax",
             "reference/node-selection/graph-operators",
             "reference/node-selection/set-operators",