Cloudstone Curio and Blessed Sanctuary on the battlefield.
Lands you control can tap to produce at least ({7} magic symbol) ({R} magic symbol) ({G} magic symbol) ({W} magic symbol) .
You have enough mana to pay for commander tax, if applicable.
Steps
Activate all mana-producing lands you control by tapping them, adding at least ({7} magic symbol) ({R} magic symbol) ({G} magic symbol) ({W} magic symbol) .
Cast Zacama by paying ({6} magic symbol) ({R} magic symbol) ({G} magic symbol) ({W} magic symbol) and commander tax, if applicable.
Zacama enters the battlefield, triggering itself, Cloudstone Curio and Blessed Sanctuary.
Resolve the Zacama trigger, untapping all lands you control.
Resolve the Cloudstone Curio trigger, choosing to return nothing from the battlefield to your hand.
Resolve the Blessed Sanctuary trigger, creating a 2/2 Unicorn creature token.
The Unicorn enters the battlefield, triggering Cloudstone Curio, returning Zacama from the battlefield to your hand.