I can't wait to see the screen installed.
Well, the wirring, basiclly depends on what parts you have. But, yes, for the PSU or inverter, you should wire directlly from the battery. It's actually not that difficult. I have km of wires running through my car, and they're all wired by me. It just takes a lot of time to do it right. So, post all the patrs you have, and I'd do my best to get you through the basics.