I typically purchase a fully-cooked ham and that will take between 12-15 minutes a pound in a 325 degree oven to properly heat to 160 degrees internal temp.
To cook the ham, I put it in a pan with a rack and pour one can of 7-Up over it and cover it. Bake to about 1/2 hour before it’s done cooking and add the glaze.
1 C. brown sugar
2 T. prepared mustard
a little pineapple juice to thin it
Once the glaze has been basted on, you can put pineapple slices over the top and continue baking the last hour.
My kids also love it if I cook the glaze on the stove and use it as a dipping sauce instead of basting the ham with it. This also gives you more options for using the leftover ham.