Since this card is a Quick-Play Spell Card, the best way to utilize it is to wait until the very last moment to use it, right before one or more of the monsters satisfying its activation condition is about to be removed by an opponent's effect. This guarantees you will know what the best card(s) is to deal with whatever your opponent plays, as well as minimize the amount of time your opponent will has to prepare for it.
You might also end up gaining a small advantage if your opponent targets this face-down card with "Mystical Space Typhoon" or is otherwise about to destroy it, because you can just chain it, wasting your opponent's card in the process.
When determining how to set up your Deck with this card, know that Fusion and Ritual Monsters have a required card(s) that are needed in your Main Deck. If you want to focus on limiting the required cards, focus on having the required monsters be Synchro and Xyz Monsters. Alone, this will still allow you to retrieve any monster in your Deck from the Graveyard or Banished Zone.
Add "Instant Fusion" to the above tip to activate the "3 or more" effect with the minimun of cards.