If somebody places an all in bet in the game and other players continue to place higher bets, the pot will be split between the players, if the main winner is the player with the lower all in bet.
For example, let's say you're playing with two other players and you all go all in. You have 5,000 chips, and the other players have 40,000 chips. If you win, you can only claim an amount equal to your bet, so you will get 15,000 – 5,000 from each player. The remaining players then compete with each other for the rest of the chips. This is how a pot is split among several players.