Start some docs on configuring

docs/configuring.rst

@@ -0,0 +1,55 @@
+.. _settings:
+
+Configuring CMake Tools
+#######################
+
+CMake Tools supports a variety of settings that can be set at the user or
+workspace level via VSCode's ``settings.json`` file. This page talks about
+the available options and how they are used.
+
+Options marked with *Supports substitution* allow variable references to appear
+in their strings. See the :ref:`var-subs` section
+
+Available Settings
+==================
+
+``cmake.buildDirectory``
+************************
+
+Specify the build directory (The root directory where ``CMakeCache.txt`` will
+be generated).
+
+- Default: ``${workspaceRoot}/build``.
+- *Supports substitution*
+
+``cmake.installPrefix``
+***********************
+
+If specified, sets a value for ``CMAKE_INSTALL_PREFIX`` when running CMake
+configure. If not, no value will be passed.
+
+- Default: ``null`` (Unspecified)
+
+``cmake.sourceDirectory``
+*************************
+
+Directory where the root ``CMakeLists.txt`` will be found.
+
+- Default: ``${workspaceRoot}``
+- *Supports substitution*
+
+``cmake.saveBeforeBuild``
+*************************
+
+If ``true`` (the default), saves open text documents when build or configure is
+invoked before running CMake.
+
+- Default: ``true``
+
+.. _var-subs:
+
+Variable Substitution
+=====================
+
+Some options support the replacement of variable values in their string value
+using ``${variable}`` syntax.

docs/index.rst

@@ -1,7 +1,5 @@
 .. CMake Tools documentation master file, created by
    sphinx-quickstart on Sat Sep 23 14:46:28 2017.
-   You can adapt this file completely to your liking, but it should at least
-   contain the root `toctree` directive.
 
 CMake Tools for Visual Studio Code
 ==================================
@@ -19,6 +17,8 @@ Contents:
     kits
     variants
 
+    configuring
+
 Developer Reference
 ===================