I've done this a couple of times in the past.

How do I make my own corned beef?

For best results, use trimmed briskets.

Start with a curing brine. This recipe makes enough for 25 lbs of meat.

5 quarts ice water (about 38-40F)
8 oz. salt
3 oz. Prague Powder #1
3 oz. powdered dextrose

Spray pump the briskets to about 12-15% of their original weight. After
pumping, the briskets are packed in a vat, and sprinkled with whole
pickling spice. If more than one brisket is done at a time, pack them
flesh to flesh with the fat sides out. Add enough brine to cover and
allow to cure for 3-4 days at 38-40F. The meat is then ready to use
(but still requires cooking).

What is pastrami and how do I make my own?

For best results, use trimmed briskets.

Start with a curing brine. This makes enough for 25 lbs of meat.

5 quarts ice water (about 38-40F)
8 oz. salt
5 oz. Prague Powder #1
5 oz. powdered dextrose
1 Tb garlic juice

Prepare and cure as for corned beef.

After curing, remove from brine and rub liberally with cracked black
pepper and coriander seeds.

Smoke at 140F until the meat is dry and then increase smoker temperature
to 200-220F and hold until internal temperature of meat reaches 170-180F.

Chill overnight before using. This meat is fully cooked.