You are allowed to purchase two items of alcohol I.e. 2 x 4 beers, one 4 beer and one bottle of alcohol. Just go to to your Carnival account on line account a few weeks before you sail and add what you want to your cart and of course pay for it. It should be in your cabin when you board.
in previous cruises I didn’t have to pay a delivery charge but now I see that I have to. So I will be looking to be like a poster on this thread saving a dollar a bottle and because of the delivery almost a dollar there too by buying at the Lido or Red Frog when I board. I will wait until we get into international waters to avoid the sals tax too. So potential savings on 8 beers is $16.