If you paste the path above into 'Run' than it should take you directly to the working WTF folder. Access 'Run' by pressing (Winkey) + R at the same time. Otherwise you may paste it into the address bar of Windows Explorer then hit Enter.

If you reinstall to a location such as C:\World of Warcraft Classic\ than your Working WTF folder will be in C:\World of Warcraft Classic\WTF\ This will make it easier for you to work with.