File Association

<   ........   Tutorial 01   ........   >

Ensure that Windows is configured to NOT hide known extensions.
Right-click to create a New > Folder
Name the folder test_01 and open it.
Right-click to create a New > Text Document
Give it the same name, test_01, and change its extension to pde
(Processing requires the file to have the same name as its folder.)

Right-click on the file and Open with > Choose default program...
Browse for the Processing executable and OK to select and confirm.
The file should now show the Processing icon.
Double-click the test_01.pde file to launch Processing.
Processing should display its Development Environment.