Listen no matter what you do, no matter who you follow, you can't mess that brisket up. Relax and enjoy your smoke, seriously. Like a pretty smart guy always says, Patience. The nice thing is you are going to eat it, it will be good, its your first brisket and you'll remember it. Seriously, if you cook it to IT the rest is all just mods that you'll continuously adjust looking for your perfect smoke. There is no perfect way, only what you cook and enjoy this time.
Don't forget the search engine also. Get out a pen and paper and figure out what you'll try this time, then next time what you liked and didn't like and how you plan to alter it to achieve your perfect smoke. Its what its all about. Its the zen of the pit.
Excuse my manners, I was brought up better. Welcome to the boards, great place with great ideas and inspirations. The folks here are all awesome and will give you more info than you can possibly digest, (pun intended there). The Guru's, OMG they know more than you can write down, AND they are pretty quick. If you have not signed up for the 5 day E course its a great starting place, AND if you are a serious smoker there are some excellent books you can get also.
Enjoy your stay and don't get too overwhelmed. If I can assist in any way, please don't hesitate to ask.
Again its a pleasure to meet you, and welcome to my addiction.
::EDIT:: I completely forgot to tell you there are quite a few coonass on the board so don't worry about needing an interputer... (chuckles)