Can someone explain this hand?

So in this hand I had K 8 and the other player had K 7 yet I didn’t get any chips and he did. Can someone explain this? thanks

You were only all in for the main pot which was won by a straight vs your 2 pair. The side pot in which you had no chips was won by the K 7 with 2 pair.

Wanted to provde the dealer chat as well:

Dealer: Dealt to board [ As Kh Jc ]
Dealer: Dealt to board [ 3d ]
Dealer: Dealt to board [ 3s ]
Dealer: bulletbob shows [ Ks 7c ] Two Pair, Kings and Threes
Dealer: hankreb shows [ Qd Js ] Two Pair, Jacks and Threes
Dealer: marks shows [ Qh Td ] Straight, Ten to Ace
Dealer: rep97 shows [ Kc 8c ] Two Pair, Kings and Threes
Dealer: bulletbob wins 8,590 chips with Two Pair, Kings and Threes (Side Pot 1)
Dealer: marks wins 8,978 chips with Straight, Ten to Ace (Main Pot)

As tabarry noted, you were only competing for the Main Pot – unfortunately!