Hello Mender,
the easiest way - if you don't like to be the leader - is: Start the mission, press the F2 key, so you are in the external view now, and have a look at your marking. In case you are wearing the "1", you are the leader of the squadron / Staffel (which will happen, in case you choose the highest rank in the beginning), - this means, you are also the leader of Rotte 1 and Schwarm 1. So the command button will give you a wide spread of possible commands to lead the AI planes in the fight (Don't forget to give the "break operation" command before using a new one).
"2" is the wingman of the leader,
"3" is the leader of Rotte 2
"4" is the wingman of "3"
"5" is the leader of Rotte 3 and Schwarm 2
"6" is his wingman
"7" is the leader of Rotte 4
"8" is the wingman of "7"
"9" is the leader of Rotte 5 and Schwarm 3
"10" is his wingman
"11" is the leader of Rotte 6
and so on.
This is for fighters only; German bombers are coded with letters.
Rotte is a pair of planes; two Rotten are one Schwarm (swarm - better known as four finger formation). Four swarms (Schwärme) are one Staffel (squadron), three to four Staffeln are a Gruppe (wing) and three to four Gruppen are a Jagdgeschwader (Group). German fighter pilots, esp. Werner Mölders, found the WWI fighter formations of three resp. 12 planes as units obsolete due to the changed velocity and tactical behavior during the Spanish Civil War. They developed the Rotte/Schwarm formation. The leaders of the Rotte (Rottenführer) are the attackers, while the wingman (Rottenflieger or Kaczmarek) give the backup and clear the six of the attacker. That way they learn by watching the manoevers. Very effective, as you can combine the firepower of the formation with learning by doing in very small and very manoeverable units.
After the Battle of Britain the Allies adopted those fighting tactics. They are still in use.
You could change your plane roughley also via the FMB - open the mission with it, choose your flight, open it and tick the player box on the bird you want to fly. Save it and it's done but won't work each time, as the seat depends on rank (see link below). You can also do it by editing the .mis-file with Notepad, look for the entry "player I_SAGr12500". This means, you are the leader of first squadron, first swarm of I.Gruppe SAGr. 125 (in code: I_SAGr125 (<- this is the unit chosen) 0 (<- 1. Squadron/Staffel) 0 (<- 1.Schwarm)).
More details on ranks and planes you can find here:
http://www.mission4today.com/index.php?name=Knowledge_Base&op=show&kid=325and here:
http://www.mission4today.com/index.php?name=Knowledge_BaseThis knowledge base is a good place to start.
Good luck!
BigMug.