Activate Zombie Infestation by discarding two cards, creating a 2/2 Zombie creature token and a 1/1 Soldier creature token.
Activate Phyrexian Altar twice by sacrificing the Zombie and Soldier.
When the Zombie and Soldier die, Tresserhorn's Lord triggers twice, causing you to draw two cards.
Repeat.
This clever loop turns the discard outlet of Zombie Infestation into a self-sustaining engine by relying on Queen Allenal of Ruadach's replacement effect to double up your token generation into both a Zombie and a Soldier. You then feed those creatures straight into Phyrexian Altar to generate the mana needed to keep discarding, while Tresserhorn's Lord, Returned acts as the ultimate payoff by drawing you a card every time a creature is sacrificed. Together, Tresserhorn's Lord, Returned also bolsters your board with its massive stat-scaling and trample, letting you churn through your deck and fuel infinite resources.