The wine packages are packages of 4, 6, or 8 bottles at three different levels (Cellar No.1, No.2 or No.3). Each of the levels has a list of wines you can choose. The 4* mariner 50% discount is not on any bottle on the wine list in a bar or restaurants. You have to buy a "package" of bottles. You can then select from the level you bought, one at a time, or order them all at once and bring them to your room.
You can bring glasses from your bottles to the Dining Room. Any unfinished bottles can be taken back to your cabin or they will hold it for you for the next night.