Firstly with any idea, especially one that you know is going to end up over complicated, best to do a few drawings 1st just to make sure it'll work, or close! :)
Step 1: Supplies.
Ok, now you think it'll work, better start thinking what supplies you'll need? In my case, trying to make my VW T4 Van 'GLOW' is going to require someone (ME!) to make a custom wiring loom! :/