Well I don’t know how to trim so there is that
Ah...then you are robbing yourself of half the fun!!!
There's TONS of videos on YouTube showing how to do it.
Right now my favorite guy is Bradley on the CHUD's BBQ channel...he seems to go along the lines that many of the pro/restaurant folks do for trimming...the key word being "aerodynamic"....to work with most of today's higher flow offset smokers.
The first thing you'll do when watching is *GASP* at how much they trim away.
This is ok, you don't waste it....I do like they do and save/freeze the scraps and when I have enough, grind them into wonderful brisket burgers, or make sausage.
Here's a couple links here that I hope will help you.
1, get a good knife for butchering, this works GREAT and inexpensive:
Victorinox 6 Inch Curved Fibrox Pro Boning Knife with Semi-Stiff Blade
Next...some videos:
How to Trim a Brisket! | Chuds BBQ
This one is Part 1 of a 3 part series that I found was VERY useful for learning brisket cooking. I will admit, at first I was a bit annoyed at Brad's presentations, but after watching a few...started catching on with the memes and humor and now I enjoy watching him.
I would recommend watching all 3 of those videos in the series above.
Here's a search result on YT for Brisket Trimming:
Search on YouTube for "Trim Brisket"
I hope this gets you started going on fully DIY brisket. It takes a bit of "just doing it"...I had a bit of trouble forcing myself to cut way THAT much brisket.
I do take a good bit of the fat and throw it in an old metal pan, and throw that pan in the smoker with the meat to render it into some smoked tallow which I'll help baste the finished brisket in.....if I wrap it in butcher paper for finish cooking I'll add the tallow there, but of late, I'm doing the foil boat method and that keeps it's own juices there so I use the rendered fat elsewhere.
Anyway.....hope this helps a bit.