Play Glacial Chasm either from your hand or from your graveyard.
When Glacial Chasm enters the battlefield, its second ability triggers, causing you to sacrifice another land you control.
Play any land from your graveyard.
At the beginning of your end step, Song of Creation triggers, causing you to discard your hand.
At the beginning of your next upkeep, Glacial Chasm's cumulative upkeep ability triggers, allowing you to choose not to pay the cost and sacrifice it instead.