In basketball, the postseason is done in a bracket format. A bracket is a visual representation of a tournament, it contains every team competing and displays which team wins in every matchup. Teams are assigned accordingly into the bracket based on their seeding. Below is an image of a bracket.
In college basketball, there is a postseason tournament known as the NCAA Tournament, or March Madness. There are 64 spots in the tournament bracket. Once the teams are selected they are bracketed into the field. This is the process by which the 64 teams are separated into four regions, each with 16 teams. In every region there are four pods with two games in it. The placement of seeds into the tournament is the same every year. For example, during the First Round, or the Round of 64, the following teams must face off against each other in all four regions:
In pod 1:
Seeds 1 vs Seeds 16 (Game 1)
Seeds 8 vs Seeds 9 (Game 2)
In pod 2:
Seeds 4 vs Seeds 13 (Game 3)
Seeds 5 vs Seeds 12 (Game 4)
In pod 3:
Seeds 2 vs Seeds 15 (Game 5)
Seeds 7 vs Seeds 10 (Game 6)
In pod 4:
Seeds 3 vs Seeds 14 (Game 7)
Seeds 6 vs Seeds 11 (Game 8)
After the rounds are completed the winners of each game in the same pod play one another. So the winner of game 1 plays game 2, the winner of game 3 plays game 4, and so on.
In the NBA, less teams make the postseason than in college basketball. The "Playoffs' as they are called, are made up of 16 teams - 8 from each conference. Teams are seeded into the competition based on their win-loss records within their conference, with 1 being the best seed and 8 being the worst. The first round matchups are based on each team's seed and go as follows.
1 Seed plays 8 Seed (Series #1)
4 Seed plays 5 Seed (Series #2)
3 Seed Plays 6 Seed (Series #3)
2 Seed plays 7 Seed (Series #4)
The tournament is then played out with the winner of series #1 facing the winner of series #2, and the winner of #3 playing #4.