Cast Time Walk by paying its mana cost, causing you to take an extra turn after this one.
Cast Vampire Charmseeker by paying its mana cost.
When Vampire Charmseeker enters the battlefield, it triggers, returning Time Walk from your graveyard to your hand.
Move to your next turn.
Activate Dour Port-Mage by paying 1 and tapping it, returning Vampire Charmseeker from the battlefield to your hand.
Dour Port-Mage triggers, causing you to draw a card.
Repeat.
This vintage combination locks down the game by chaining infinite turns together using Dour Port-Mage to repeatedly bounce Vampire Charmseeker back to your hand. Each time Vampire Charmseeker enters the battlefield, its triggered ability plucks Time Walk right back out of your graveyard, letting you cast it again to secure another turn. Meanwhile, Dour Port-Mage’s activated ability is further rewarded by its own passive triggered ability, which keeps your hand full by drawing you a card every time the Charmseeker leaves the battlefield without dying.