Id add to this that you need to get a whole packer brisket, not just the flat from the grocery store, otherwise it'll dry out on you. Look for a uniform thickness if you can, and don't be afraid to get the choice cut over prime, it's not worth the extra spend and can get too tender.
Assuming you are using butcher paper? For the rest I usually line my cooler bottom with cardboard, insert the brisket, then put a layer of cardboard over the papered brisket. That way you don't get murdered by your wife for beef grease stains on your towels. Also fun to dry off with a brisket scented towel...