-First, mulligan until you get a Treasure Hunt in your starting hand.
-Turn 1: Play an Island.
-Turn 2: If you have a Reliquary Tower in your hand play it, then play Treasure Hunt. If you don't, play a Swamp.
-Turn 3: If you don't have a Reliquary Tower in your hand yet, play Treasure Hunt before you play your land, then play your newly found Reliquary Tower. If you accomplished the above step on Turn 2, play a Swamp followed by Zombie Infestation if you have it.
-Turn 4: If you don't have a Zombie Infestation yet, play another Treasure Hunt. Play a Swamp, then play Zombie Infestation. Once you have Zombie Infestation on the board, discard everything you can to produce a hoard of 2/2 Zombies. If you played Zombie Infestation during your last turn, attack. For a stronger attack, play
Contested War Zone
and activate it before resolving combat damage.
-Turn 5: Play and/or activate
Contested War Zone
and attack. If you need more zombies, play another Treasure Hunt to acquire more cards to discard. Be careful not to mill yourself out.