If you have a team account, you do not have to set up a new log in to manage your child's athlete account. Once your athlete has created their account, they can go to the "People" section and add your log in email for CaptainU. This will grant you Parent access.
The next time you log into your team account, click the "You" tab on the toolbar at the top of your screen. Select "Log into athlete account" from the dropdown. If you have multiple athlete accounts, you will be able to select which one you want to access.