Traditionally, the first step in being a dealer is to shuffle the cards. There are many different shuffling methods, such as the riffle shuffle, the overhand shuffle, and the strip shuffle. You can find some tutorials on those methods (and more) here and here.
Once the deck has been shuffled, then you’ll be expected to deal the cards. Pass out a number of hands according to the number of players and a number of cards according to which game you’re playing. Next, check your partner’s sleeves. If you find an ace, you’re dealing with an ace partner. Place the ace back into the deck, recollect all the hands, and shuffle again.
Many people report facing greater difficulty in shuffling a deck that includes a human-sized ace, but rest assured, it can be done. Popular wisdom suggests you can replace the ace with a card-sized replica to stand in for them, but some dealers feel this amounts to glorified cheating. In the end, the decision is up to you. Alternative methods include the pathos shuffle, which involves allowing your ace partner to use merely their hand as a component of the deck and shuffling with it as if it were a card. Specialized rectangular gloves are available to facilitate the squaring of the deck in this process. Make sure your ace partner is properly costumed, as well, to blend in with the rest of the cards and to make them more difficult to notice for the other players.
For less sarcastic advice, try What To Do If You Think Your Partner Might Be Asexual, on my ace-allo relationship, this “Allosexual dating Ace” reddit thread, Asexual/Allosexual Relationships, Asexual/Allosexual Relationships and Sex, and Why Date An Asexual? An Interview with C.