You have a land card in hand that enters the battlefield untapped.
Steps
Activate Walking Atlas by tapping it, putting a land from your hand onto the battlefield.
The land enters the battlefield, triggering Tireless Provisioner and Retreat to Coralhelm twice.
Resolve both Tireless Provisioner triggers, creating two Treasure tokens.
Resolve both Retreat to Coralhelm triggers, untapping Walking Atlas and choosing either to untap another creature or scry 1.
Activate a land by tapping it, adding at least ({1} magic symbol) .
Activate both Treasure tokens by tapping and sacrificing them, adding ({R} magic symbol) ({G} magic symbol) .
Activate Mina and Denn by paying ({R} magic symbol) ({G} magic symbol) and returning a land from the battlefield to your hand, giving a creature trample until end of turn.