Mix up the marinade. and marinate your roast overnight. I like to use gallon-sized bags to marinade meat like that. You can also freeze meats in the freezer bags with the marinade. Just pull the meat out of the freezer to defrost the night or two before you want to cook it. This is a great way to take advantage of some of the deals at the warehouse stores.
If you remember, pull the roast out of the fridge an hour or so before you start cooking. I forgot to do this so added a bit of time to the cooking.
Preheat the oven to 325 or 350. (The recipe calls for 325. I forgot to pull the meat out AND it was going to be a late dinner so I cooked it at 350 and it came out great.)
Put the roast on a rack in a roast pan and pour the marinade over it. Bake 1.5 to 2 hours, basting now and then. If the juices in the bottom of the pan evaporate, add a cup of water. Check with meat thermometer and pull the roast out when it hits 150 degrees F. Cover with a foil and let it sit for 15 minutes or so, while you cook up your side dishes, set the table, etc. Carve the meat into slices.