Hello people! Just do like caldaar says!!!
You gotta reassign the controller (supposing you have only one, like me). Then you go back to the game, set up the other player, and you go back, reassign the controller back, and just do it as many times as it is requested (great way to think outside the box!, THEY GOTTA FIX THAT) . I am about to play our first song, bass - guitar setup, i paused for sharing it with anyone stuck like i was. Thanks caldaar!!!