Activate Mind Over Matter by discarding a card, targeting an artifact, land or creature an opponent controls.
Marchesa and Bone Miser trigger.
Resolve the Bone Miser trigger, either adding , creating a 2/2 Zombie creature token, or causing you to draw a card.
If you created a Zombie token and your mana pool is empty, activate Phyrexian Altar by sacrificing the Zombie, adding 1.
If you drew a card and your mana pool is empty, activate Mind over Matter by discarding a card, targeting any permanent you control, triggering Bone Miser.
Repeat from step 3 until you have resolved all Bone Miser triggers and have at least 1 available.
Resolve the Marchesa trigger from step 2, causing you to pay 1 to look at the top two cards of your library and put one into your hand and the other into your graveyard.
Repeat.
By leaning on Mind Over Matter to repeatedly discard cards, you kick off a cascade of triggers where Bone Miser turns every discarded creature, land, and noncreature spell into a steady stream of mana, bodies, and card draw. Phyrexian Altar is on hand to sacrifice those generated Zombie tokens for extra fuel whenever your mana runs low, ensuring the engine never stalls. Meanwhile, Marchesa, Dealer of Death treats these targeted discards and interactions as crimes, letting you sink a small amount of mana to aggressively filter through your deck and curate your hand and graveyard.