Running 12v appliances off battery

I have just purchased a 100w starter kit with wanderer charge controller. I understand the wiring to the panel and battery but I have already wired in lights and 2 12v sockets in my van which I want to run off the battery.

How do I connect up the battery to these devices, what wiring? Fuse box? Etc would I need. I have no desire for an inverter as all my electrics are USB/ 12 volt. Any diagrams would be great also.

I am a complete novice, so any help, no matter how simple would be appreciated.

Thanks