From the Dashboard, Select "Club Management" followed by "Teams" here in the top tabs you will select "Teams", scroll down and Click "Roster Builder"
Here you will select your "Event" and hit submit.
Once here, you will click and drag the hairpin icon next to the players name to the team you would like to roster them on.
Note: All the players on the team currently have green checkmarks that signify approved.
You will now see that player on the team with a Yellow Triangle next to his name since he was just added and has not been approved yet.