When I start a 2D game with human control I still cant change Players and they are in for ever. Is this a Bug or am i too stupid?

To make subs you have to wait for a deadball and then click the icon with the arrows making a triangle and that will bring up the substitution screen. From there click the row of the player you want to sub in and then click the photo of the player you want to sub out and it will make the change.

However if you have created a league where you are playing in local mode as the GM only then even though the team is human controlled you are not the coach so you cannot do anything but watch the game. In that case you could fire the head coach and name yourself as head coach and then would control all items of your team.

Many thanks for the quick reply!