Basically, during the normal qualification process (which starts in March 2021) there will be 10 groups, with the winners qualifying automatically for the finals.
The 10 runners-up will then be joined by the two best Nations League group winners that failed to finish in the top two of their qualifying group.
Those 12 teams will be drawn into three different play-off paths. There will then be two semi-finals and a final in each path, with the three winners making the World Cup. Got all that?