Point systems can vary as much as leagues do. It is a rule that can be voted in by league vote, and supersedes ABC guidelines, unless it can be proved to favor one bowler over another.
Basically there is game point, match point, and a combination of the two.
Game point is x points per game, and x points for total pin fall.
Match point is usually each player against his opponent on the other team. The winner is awarded a match point. So on a five person team there would be 5 match points. In addition there is usually x team points for the game win, and x points for total pin fall for the series.
Some common ones are 1 point for each game, and 1 point for totals, a 4 point system. 2 points per game, and 1 for totals, a 7 point system.
In match point it varies a lot depending on the size of the teams. Many will use a 24 point system and divide the wins accordingly into 24. So say you have 4 person teams, then 1 match point per member, and 4 per game for a total of 8 possible per game, three games makes 24 total points possible. Some may want to have total pin fall in there, so they make it 1 per player, 3 per game, and 3 for series. Still equaling 24 total possible points.
It can be virtually anything you want it to be as long as it is fair to all.