Euro 2020 qualifiers get under way on Thursday with 24 places up for grabs at next year's tournament, which will be held in 12 countries across Europe.
How does it work?
UEFA's 55 nations have been split into five groups of six teams and five groups of five. Each team plays home and away against the other teams in their group with the top two from each section becoming the first 20 teams to qualify.
What about the Nations League?
The traditional qualifying groups are the easy part, deciding the contestants for playoffs to decide the remaining four places is a rather more complex process.
UEFA's inaugural Nations League played in the Autumn of 2018 split the 55 members into four tiers (League A-D) with four groups in each.
The 16 Nations League group winners have the safety net of a playoff but will only take part if they fail to make the top two in their qualifying group.
Those 16 nations are:
League A: England, Netherlands, Portugal, Switzerland
League B: Bosnia and Herzegovina, Denmark, Sweden, Ukraine
League C: Finland, Norway, Scotland, Serbia
League D: Belarus, Macedonia, Georgia, Kosovo
Each league will have a path of its own, all of which will feature two single-leg semi-finals and one single-leg final. The winner of each path will qualify for Euro 2020.
All nations were ranked 1-55 on their Nations League performance based on where they finished in their group, points won, goal difference etc.
If a Nations League group winner also finishes in the top two of their qualifying group, their spot will go to the next best-ranked team in their league.
What about the Nations League finals?
As group winners in League A, England, the Netherlands, Portugal and Switzerland will contest the first Nations League finals in June.
The outcome of the finals will have no impact on who qualifies for Euro 2020.
When are the matches played?
All qualifying matches will be played between March and November 2019, with double-headers in March, June, September, October and November.
Those sides involved in the Nations League finals will not have any qualifiers in June.
When and where does the tournament take place?
The 12 host cities are: Amsterdam, Baku, Bilbao, Bucharest, Budapest, Copenhagen, Dublin, Glasgow, London, Munich, Rome and Saint Petersburg.
The tournament will take place between 12 June 12 and 12 July 2020.