The remote turn on wire? It's only necessary if you have an amplifier. Don't get in the habit of thinking every wire needs to be hooked up--it can be damaging.
There are a couple of ways to connect a wire (I'm assuming your yellow battery constant):
Built in tap on the fuse: Different kind of tap built in: My personal favorite and probably the cheapest, a simple metal tab that you can slip on any existing fuse.
