This is a step by step installation of Visual Studio Code for Windows, in addition to the installation of Dart.
Environment variables: Change "user-name" with your login name for Windows.
C:\Users\user-name\AppData\Roaming\Pub\Cache\bin
An alternative way to access environment variables:
Open file manager. At the location bar, type in "control panel" and hit enter.
Control Panel - User Accounts - User Accounts - Change my environment variables (located on the left side)