The field of 16 in the Stanley Cup Playoffs is set with the top three teams in each of the four divisions automatically qualifying. Then there are two wild card teams in each conference, determined by which teams are the next two highest finishers in their conference.
In the first round, the division winner with the best record in the conference plays the team with the lesser record between the two wild card teams; the other division winner plays the wild card team with the better record. The teams that finish second and third in their divisions play each other.
Each round of the Stanley Cup Playoffs is a best-of-seven series, so the first team to win four games will advance to the next round.
There is no reseeding. Once the bracket is set, it follows that format all the way through to the Stanley Cup Finals.