How Do the NFL Playoffs Work
After the division winners are determined, the next 2 teams with the best record will qualify for the Wild Card Round. The wild card team with the best record will get seed 5 and will play seed 4 of the division winners. The worst record of the 2 will get seed 6 and play seed 3 of the division winners. There are 2 wild card teams from each conference.
The NFL does not run a "true" bracket, like you you see here on the March Madness Bracket or on the NBA Playoff Bracket. I define a "true" bracket as a tournament where the winner of each game moves directly over in the bracket. The NFL Playoff bracket rearranges the bracket in the second round so that the highest seed(1) in each conference plays the lowest remaining seed in the same conference. The rearranging only takes place if the 6 seed upsets the 3 seed in the wild card round. When this happens the 6 seed moves up to play the 1 seed and the winner of the 4 seed vs 5 seed game will move down to play the 2 seed.
Otherwise the bracket plays out true. Here is an example of an NFL Playoff Bracket where the second round shuffle was done.
As you can see on the AFC side the number 6 seed Baltimore beat New England and therefore since they were the lowest remaining seed they went up to play the number 1 seed Indianapolis. If you look at the NFC side it played out true, as the number 3 seed Dallas beat the number 6 seed Philadelphia, which left the number 4 seed Arizona as the lowest remaining seed to play the number 1 seed New Orleans.