Yeah sorry it wasn't clear, I could see it in my head but didn't know how to put it into words.
So you are going to pick 2 teams that will play against each other which are made up from players who have been in a squad that was relegated and a team from a squad that was promoted.
A player can only feature for one side so either the relegated side or promoted side. You can only choose 4 players max from a season e.g. 4 players from the 1994/95 relegation season.
Hopefully it's a bit clearer.
Here are my teams
Relegated team:
Ruddy - 2013/14
Martin - 2013/14
Bowen - 1994/95
Newsome - 1994/95
Shackell - 2008/09
Redmond - 2015/16
Crook - 1994/95
Francis - 2004/05
Eadie - 1994/95
Ashton - 2004/05
McKenzie - 2004/05
Subs
Green - 2004/05
Klose - 2015/16
Howson - 2015/16
Fer - 2013/14
Snodgrass - 2013/14
Elliot Bennett - 2013/14
Jerome - 2015/16
vs
Promoted team:
Krul - 2018/19
Aarons - 2018/19
Drury - 2003/04
Fleming - 2003/04
Mackay - 2003/04
Buendia - 2018/19
Hoolahan - 2010/11
Johnson - 2014/15
Huckerby - 2003/04
Pukki - 2018/19
Holt - 2010/11
Subs
Forster - 2009/10
Whitbred - 2009/10
Tettey - 2014/15
Fox - 2010/11
Russell - 2009/10
Hooper - 2014/15
Jackson - 2010/11