You are going to need a large pit BBQ with a cover to completely cook outside- or you can finish this off in the oven.
Completely cover the brisket with the steak seasoning- don't be stingy- and pat in well or"rub" as we do here in Texas.
Seasoning layer should be thick.
Place brisket over coals located on one end of pit or in BBQ and sear all sides of brisket, watching for flame ups, for 2 hours.
Use heavy duty foil and completely wrap brisket, placing in a pan that brisket fits comfortably Move pan to the side of the pit without the coals- or to your oven, set at 325 degrees- and let cook for 3 hours, replacing coals to keep temp in your pit at about 325-350 degrees.
Remove pan and let brisket set for 15-20 minutes before slicing.
Be sure that you slice against the grain of the brisket or it will be tough.
There will be lots of wonderful au jus in the foil, be sure to pass that with your brisket and serve with pintos, cornbread and slaw.