The NFL has 2 conferences, the AFC and the NFC. Each conference has 4 divisions, with 4 teams in a division thus a total of 16 teams. .
In each conference, 6 teams qualify for the playoffs. So, of the 32 teams, 12 advance to the playoffs.
In each conference, the 4 division winners earn a playoff berth. They are seeded #1 through #4 based on their won/loss record. The team with the best record gets #1, second best #2, etc.
Then in each conference the 2 teams with the best won/;loss records that didn't win a division qualify for the playoffs as seeds #5 and #6. These 2 teams are called wild cards.
Since there are often ties for best won/loss records, the league has established tie-breaker systems that are used if needed to seed the division winners #1 through #4 and to select and seed the 2 wild card teams #5 and #6. The link below points to a website that explains the tie-breaker process.
So, now in each conference the 6 playoffs teams are seeded #1-#6. The #1 and #2 seeds get a first round bye. The first round of the playoffs is called the wild card round, or sometimes you hear it called "wild card weekend"
You really can't set up a playoff bracket yet because the round 2 match ups depend on the seeds of the teams that win the wild card games.
For the wild card round, the #3 seeded team hosts the #6 seeded team, and the #4 seeded team hosts the #5 seeded team.
So wild card weekend has 2 games in each conference, 4 total. Usually, 2 are played on Saturday and 2 on Sunday so they can all be seen on TV by fans.
The second round of the playoffs is called the Divisional Round. Each conference has 4 teams remaining and you can now set up a playoff bracket that leads to the Super Bowl.
For the divisional round, in each conference, the #1 seeded team hosts the lowest remaining seeded team that won a wild card game. And, the #2 seeded team hosts the other wild card weekend winner.
So there are 4 games for the divisional round, 2 in each conference. And, 2 are played on Saturday and 2 on Sunday.
The 3rd round games are called Conference Championship Games. The winners of the divisional round play for the AFC title and the NFC title. For these games, the highest remaining seeded team hosts the other divisional round winner. The 2 games are played on Sunday.
Then of course, 2 weeks later, the winner of the AFC and the winner of the NFC play in the Super Bowl.