Put roast in a crock pot. Sprinkle the 3 dry mixes over the roast and add 2 C water. Cook on low for about 8 hours. Remove meat and thicken juice with cornstarch and cold water mixture to make roast gravy, or use the juice for dipping. I like the gravy myself.
I prefer an Arm Roast, but any cut will work. If you do not plan to make gravy, only add 1 cup water to the crock pot.