No worries ! A lot is going under the hood and what's there is absolutely rough.
What was the problem ? After the team folder is created youn need to click on it then affect 5 players from your pool on the right.
After this is done you can click each player individually (on their summary on the left side of the screen) then place them in the little "placement" blackboard. Once this is done you should be able to click "submit" and your team will be created.