Select Casual Games under Multiplayer
Game Type: Tournament
Buy in: 100 (or whatever you feel comfortable with)
Wait for 6 players total to join.
to GO and
to ready up.
On Buy in 100 most players go all in on the first hand. After knocking out the other 5 players will net you the achievement. If you want to grind this out go to a higher buyin and wait for premium hands.