After a 3-1 start to the season, the Boston Celtics will play host to the Chicago Bulls on Friday night at TD Garden (7:30 p.m. ET).

The Celtics played the Bulls earlier this week, winning 134-99, but this game will be different because it's part of the NBA's in-season tournament: The NBA Cup.

Here's what you need to know in advance of the NBA Cup.

The Cup is the brainchild of NBA Commissioner Adam Silver, who modeled it after European soccer. The tournament began in 2023, making this the fourth edition of the event.

The Los Angeles Lakers won the first tournament while the Milwaukee Bucks won the second and the New York Knicks won the third.

The Knicks became the first team to win the NBA Cup and the NBA Finals in the same season. And yes, there is a banner at Madison Square Garden for both.

It's somewhat complex, so here we go:

1) The 30 NBA teams have been split up into six groups of five. Three groups make up each conference.

2) The Celtics are in Eastern Conference Group C with the Bulls, Atlanta Hawks, Washington Wizards, and Charlotte Hornets. The Celtics will play each of these four opponents.

3) Two of those four games will be played at home, and two will be played on the road.

4) All of these games count toward the regular season standings, except the NBA Cup championship. 

5) Eight teams will advance to the elimination round. The top teams from each group make up six of the teams, plus two wild cards, one from each conference.

6) If a team does not advance to the elimination round, they will play two NBA Cup teams that also failed to advance, which helps make up the full schedule for the season.

Because those two teams will have played 83 games, more than the other teams.

A trophy, a banner (apparently), and a prize of more than $500,000 per player. That might not matter much to Jayson Tatum, but it can be a big deal for guys at the end of the roster, and that often motivates everybody.

Group play games happen on a variety of different nights, but the Celtics will play the Bulls on Friday, the Hornets on Nov. 6, the Wizards on Nov. 24 and the Hawks on Nov. 27.

The quarterfinals are Dec. 4-5, the semifinals are Dec. 8/9 and the title game is Dec. 11.