Freeze them first, then steam them when you are ready to serve. Don't know what the steam does, but it sure makes them taste good....
Do I Freeze Tamales Before Or After Steaming?
You should steam them FIRST to make sure they get fully cooked, and then you would freeze them. When you take them out of the freezer, let them thaw out. Then put in the microwave for a minute or two to reheat.