So that I don't have to go through the trouble of writing out the whole process I will include a link that gives a fairly good go at it
It is Paula Dean from FOOD TV
The key is really the cooking process that makes it tender.
A few caveats:
Find a rub that you like and use that.
Get a BBQ sauce that you like and heat it and the pan juices together, put it on the plate when serving, nobody likes brisket smothered in sauce.
Trim "excess fat before cooking" leave some fat but if you have large pieces of really thick fat, trim that down that way it will disolve during the cooking process.
Stick with an oven if you don't have a decent pit and KNOW how to use it. This is NOT grilling.
For extra goodness make a marinade, get an ice pick and go fatal attraction on brisket then pour on the marinade and stash in the fridge for 2 days. flip after a day. When you pull it out dry it and put on the rub, continue with instructions.