Welcome to the site, Cucklebur! First thing I'll say is it's not done until it's done. Don't go by time or temp(of the meat). I just did a packer yesterday that hit the "wall" at 150 and wasn't done until internal temp of 209.(I might have a bad probe or two)
Everyone has their own way and you'll have to find yours. My way is to rub it down w/worchest sauce or dales steak seasoning/marinade(basic soy sauce and worchest), then add k. salt, plenty of blk pepper, and maybe some tony c's creole mix. Then on the smoker(pellet smoker), fat down(due to heat from bottom), at a pit temp of 225-300. I like 250, just what works for me. Once the meat temp hits around 170 or so I put in an alum foil pan and cover w/foil until it's ready. Don't think it is done when the temp won't rise, that would be a mistake....unless your boots need new soles.
You'll know when the brisket is ready when you can slide the meat probe into the flat with little resistance. It takes practice to know when, going in like butter is too tender for us so I like just a tad of resistance.
Keep it simple for now, just get your feet wet and then you'll know exactly how you'll want to do it.