Once the application is installed, all you have to do is right-click on the folder you want and choose the 'map virtual drive' option. After this, a small window will appear where you can choose the type of drive and the name you want.
To remove a folder as a drive, all you have to do is reverse the process: right-click the drive and select the 'unmap' option.
Vonuff Vdrive is a very useful application, that's also very easy to use. The interface is far from complicated, and you can do everything right from Windows Explorer.