You choose a total of 14 players, obviously 3 subs. You can play any formation within reason (442, 352, 433 or 343), by swapping players about when you're finished selecting them all.
If it's still putting Adriano in goals for you I dunno what's goin on. :lol:
The transfer thing is necessary later on as teams are eliminated. It also deducts points from your total if you transfer players just because you feel like it.