The 12 teams will be drawn into 3 paths to qualify.
So there will be 3 places up for grabs and 4 teams will fight it out for each spot, there will be a semi final and a final.
Seeded teams will play the semi final at home as all fixtures are just one leg. Final location is based on the draw.
A bit confusing but that's what I got from it.
Thanks, got this from Sky Sports:
The play-offs take place from
March 24 to 29 2022, with 10 group runners-up joined by the two best group winners from the 2020/21 UEFA Nations League overall ranking that have neither qualified directly as group winners nor entered the play-offs already as group runners-up.
During a play-off draw on
November 26 2021, those 12 teams will be drawn into three play-off paths for one-off semi-finals and a final, with the three path winners then qualifying for the tournament in Qatar.
The draw will be seeded based upon qualifying-round points. The six best runners-up will be seeded and play their games at home, while the remaining four - plus the two UEFA Nations League teams - are unseeded and will face an away tie.
The draw will take place in Zurich on Friday November 26 from 4pm, UK time.
The six best-ranked runners-up - based on criteria that starts with number of points, goal difference and goals scored - will be allocated to Pot 1 and drawn in six semi-finals as the home team.
The remaining teams will then be drawn from Pot 2 to semi-finals 1-6.
There will be three play-off paths, with each providing a World Cup finalist.
Semi-finals 1 and 2 make up play-off path A, semi-finals 3 and 4 form path B and semi-finals 5 and 6 will contest path C.
To determine which semi-final winner will play at home in the final, an additional draw will be held for each path.