Scirocco Register

I've had a look on the FAQ which has an easy guide to what relay pins do what. What I need to know is how to attach wiring to the back of the fuse box without screwing anything up? I guess i probably want my switched lives to go through a fused pin? And am i splicing wires or fixing to pins at the back of the fusebox? Earths are relatively simple i guess, just attach spade connectors to the collection of earths on the right of the fusebox.

Could run them independant of the fusebox and just have an inline fuse in the wire instead. I have a set-up like this for my fuel pump at the minute, works well.