You actually have a pretty small brisket, usually you can find them in the 13# to 16# range. Now this could be a good thing as it will cook faster and you might not have to do a lot of trimming, but take the fat cap down to 1/8 to 1/4", and on the fattier "point" muscle, remove the edge fat and cut some of the fat seam away.... it's just too heavy to ever render out during the cook. If you see any small tags or fingers of meat, cut them off as they will just burn.
When you are through trimming, note the grain direction in the flat muscle. When slicing you need to cut against the grain. I recommend making a thin V notch to identify the grain direction. Once cooked the V notch will have opened and be easily seen. You slice across the V, see photo at the bottom and this will make sense.
Seasoning is a personal taste, but use at least salt and pepper. Adding garlic powder and onion powder works too. I've injected briskets for many years, even a jazzy beef broth or aujus will add some flavor and moistness.
Smoking in the 250° to 275° gives you more control. Many competition cooks use higher pit temps, but you really have to be on the ball.
I use a wrapped step for moistness and tenderness, this is not mandatory but for your first few I would recommend wrapping at 165° internal temp (fat side up) in a double layer of foil, adding a couple of ounces of some beefy broth before sealing the foil. Return to the smoker and check tenderness in an hour. Keep cooking until it probes tender, don't pay attention to internal temp, you want to feel that it's done. An easy method is to use a bamboo skewer, or an ice pick etc. Take a jar of peanut butter and probe it a few times paying attention to the way the probe feels in both directions. This is the "feel" you want on the brisket flat muscle. Don't worry about the point, it will take care of itself.
Now up to this time you can do everything correctly, but if you don't rest in an insulated cooler for at least 2.5 hours (I prefer 3 or even 4 hours) it won't come out right.
EDIT - the photo does not want to load. I'll try again later, but click
HERE and is should open up.