As you board and encounter your first ship's security person, ask them for the location of your Muster Station.
Muster stations are located on deck 7, Promenade deck. Muster station "A" is located in the Princess Theater, then B, C, D etc moving aft on deck 7. Knock that out as soon as you board and then watch the muster movie on your smart device while you have lunch waiting for your room to open.