I don’t understand what you mean it is open when you start a game.
It's even in the game manual!
Load the game up, click start new game, select the leagues you want to play and click confirm, it'll start the league loading process, then it pops up with a small window to add a manager, click next, add your name, click next, add your nationality click next, add your team and
fav team click next, then it tells you to add your pic, select it and search for the pic.
If you didn’t get that pop up go into preference and make sure the add manager wizard is selected.