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 the "Event" and hit submit.
Once here, you will click and drag the hairpin icon next to the player's 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 by the event.
You will now see that player on the team with a Yellow Triangle next to the name since the player was just added and has not been approved yet.
All New players will appear with Yellow Triangles until the roster is approved by the event.