Cast Temporal Manipulation by paying its mana cost, causing you to take an extra turn after this one.
Cast Possessed Skaab by paying its mana cost.
When Possessed Skaab enters the battlefield, it triggers, returning Temporal Manipulation from your graveyard to your hand.
Move to your next turn.
Activate Dour Port-Mage by paying 1 and tapping it, returning Possessed Skaab from the battlefield to your hand.
Dour Port-Mage triggers, causing you to draw a card.
Repeat.
This brilliant loop centers on Possessed Skaab, which immediately returns Temporal Manipulation to your hand as it enters the battlefield from your graveyard. Once you have a Dour Port-Mage on the board, its activated ability lets you bounce Possessed Skaab right back to your hand for cheap, drawing you an extra card in the process thanks to Dour Port-Mage's triggered ability when a creature leaves the battlefield without dying. By recasting Temporal Manipulation and repeating this cycle on your extra turns, you secure infinite turns and a bottomless card draw engine.