You have an instant and/or sorcery card in hand that can target a creature.
Opponents control a number of enchantments equal to or greater than five plus the mana value of the instant or sorcery card.
({2} magic symbol) ({UR} magic symbol) ({UR} magic symbol) plus enough mana to cast the instant or sorcery card available.
Steps
Activate Soulfire Grand Master by paying ({2} magic symbol) ({UR} magic symbol) ({UR} magic symbol) , causing you to put the next instant or sorcery card you cast into your hand instead of your graveyard as it resolves.
Cast an instant or sorcery spell by paying its mana cost, targeting Dockside Extortionist.
Orvar triggers, creating a token copy of Dockside Extortionist.
The Dockside Extortionist token enters the battlefield, creating a number of Treasure tokens equal to the number of artifacts and/or enchantments opponents control.
Resolve the instant or sorcery spell, returning it to your hand.
Activate any number of Treasure tokens by tapping and sacrificing them, adding ({2} magic symbol) ({UR} magic symbol) ({UR} magic symbol) plus enough mana to cast the instant or sorcery card.
Repeat.
Once you have infinite mana, you may target any permanents you control in step 2 to create infinite token copies of them.