Sidisi triggers, searching your library for Ascend for Avernus and putting it into your hand.
Activate three Treasure tokens by tapping and sacrificing them, adding ({W} magic symbol) ({W} magic symbol) ({W} magic symbol) .
Cast Ascend from Avernus by paying ({5} magic symbol) ({W} magic symbol) ({W} magic symbol) ({W} magic symbol) , returning Sidisi, Riftsweeper, and Dockside Extortionist from your graveyard to the battlefield, and exiling Ascend from Avernus.
Sidisi, Riftsweeper, and Dockside Extortionist enter the battlefield, triggering their abilities.
Resolve the Dockside Extortionist trigger, creating at least five Treasure tokens.
Resolve the Riftsweeper trigger, shuffling Ascend from Avernus into your library from exile.