Log in to your account on the VDJ webpage (the one where you registered your serial key and downloaded the software), then go to the download section and download the basic mapping for the DDJ-SB.
Install this mapping and you should be basically good to go.
If you want anything to function otherwise than in the default mapping, go to the VDJ wiki on the profile page (select your profile on the VDJ page, go to support -> wiki) and look for “midi mapping”. The article there is pretty extensive and will show you how to do all of what you like to achieve. Basically VDJ is extremely open and you can do pretty much anything.