This article goes into more detail about the different settings you can apply to your knockout brackets. For instructions on how to actually set up your playoffs, please see this article.
When you click Add Bracket, you will see this dialog:
This is where all the settings described on this page are made.
Single Elimination
This is the default format. To set up a standard single-elimination bracket, you just need to enter the number of teams and click Save Bracket.
Consolation Modes
Consolation modes determine what happens after a team loses a game.
Full Consolation
Gives all teams in the bracket the same number of games. Losers are not eliminated, they simply drop to a lower bracket and keep playing until each rank is determined. That means, for instance, in an 8 team bracket with full consolation, everyone gets 3 games. If you lose your first game and win the remaining 2 games, you've come in 5th. If you lose your first 2 games and win the third, you're 7th. And so on.
Here's an example 8-team full-consolation bracket:
Third Place
Adds a third place playoff match for the losers of the semi-finals (like FIFA World Cup, for instance) – nothing else. This would be like the example above, just without the bottom (5th place playoff) bracket.
Double Elimination
It takes 2 losses to be eliminated from the tournament.
The winner of the Losers' Bracket (LB) meets the winner of the Winners' Bracket (WB) in the Final.
The LB winner has to beat the WB winner twice in order to be crowned champion (otherwise WB winner would have been eliminated after 1 loss).
This is why you see a Secondary Final on the schedule. If you do not want to play this game, you can simply leave it unscheduled or put it at the same time as the Primary Final and enter the same score again if needed. It can't be deleted from the schedule currently.The WB winner only has to beat LB winner once.
Here's an example 8 team double elimination bracket:
Two-Legged Ties
Teams face each other twice; the better team after both games advances. If you do not check two-legged final then the final will be just one game (same as UEFA Champions League, for instance).
Currently, there needs to be a definitive winner (one team needs to have scored higher on aggregate) in order to advance. If you have a tie, please increment the score of the team you want to advance by 1.