Its a lot of wires but only one of them has to be joined and you can even twist that around the existing connector base and pop a little insulation tape on if you don't want to splice it, the others bits are new pins that slot into their holes, the bcm plugs come out easy and slide apart easy to get the new wires in, easier than the smaller ones and the other connection is a ground which you will find below the front passenger side fuse box.
I know its daunting but after pulling the trim off and having a good look at one of the plugs its not too bad, honest!
I take it you have already had the trim off in the passenger footwell? If not I have the manuals which basically tell you to pull it off