Step 3: Start a command window and Notepad

Put the mouse cursor in the right panel of the Explorer window. Make sure no file names are highlighted. Left-click in a blank space in the window to un-highlight any file. (If you just created the folder, there will be no files, so this is not needed.)

SHIFT-RIGHT-click in the window.

A menu will pop up. Click on "Open Power-shell window here". (Depending on your revision of Windows, this may be some other similar command window.)

The command prompt is the part PS C:\JavaSource>

In this minimalist environment, you enter commands to the OS by typing them after this prompt. To start Notepad, type notepad after the prompt. Hit "enter".