There are 4 available Mappings for Keyboard to choose from and match your workflow. Visit VirtualDJ Settings -> MAPPING tab, click on Keyboard from the Devices list and select your preferred Mapping or edit/create a Custom one.
The factory default Mappings are explained in the following chapters
Default (Rekordbox compatible)
Default (Serato compatible)
You can customize the keyboard mapper should you want. Learn more about mapping here