Place the corned beef brisket in the crock pot, fat side up
Sprinkle the included seasoning packet over the meat
Add enough water, beef broth, or a mix of both to cover the brisket
Add optional vegetables like onions, carrots, and potatoes around the meat
Cover and cook on low for 8 to 10 hours, or on high for 4 to 6 hours
Check that the corned beef is fork-tender before removing it
Transfer the corned beef to a cutting board and let it rest for 10 to 15 minutes
Slice the corned beef against the grain
Serve with the cooked vegetables and some of the cooking liquid if desired