Once you have selected the session type and the team and assigned a name to the session, a list will appear with the team players:
Press and hold on the player's name you want to remove
The "Delete" option will appear in the upper right part of the screen. Select "delete".
A window will appear informing that you are about to remove a player from the session. Confirm the player removal by pressing "yes".
The player will have been successfully removed from the session.