From a relative newbie using the Cookshack for brisket, here is some advice.
Do not use too much wood. Three or 4 oz of hickory for a brisket might be enough for your first attempt.
I use JJ's rub (look in recipes section)applied after slathering the brisket with French's mustard. Let it sit in frig covered overnight and the let her rip in the Cookshack. You need an internal temperature probe (like a Polder) to help determine when the brisket is done. Depending on when you are going to eat the result, you might take it out at 190+ to 200+ degrees internal temp.
Make sure you have opened the holes in the aluminum foil you lined your unit with. Make sure you have a drip pan installed in the proper place. Make sure you empty this periodically- it might overflow!
Read Smokies' Brisket 101 for good advice on doing a chunk of chest in the Cookshack. Pay attention to the plateau temp of this cook. You may think nothing is happening to the brisket, but here is where the magic of Que is happening.
And, do not open the Cookshack to often. Each time you do extends the cooking time significantly. If you start a cook in the early morning hours, and keep peeking into the Cookshack, you might not get the brisket done when you expect it to be done. Resist the temptation to take a peek unless you have a good reason.
Good luck.