Hi Lisa,
It should be easier, but after reporting this issue to AAT, we have been informed that the 'Green Light' system cannot authenticate your MyAAT account details. This means you have to access the Green Light test via the MyAAT 'study support search' page. When you click the links from the 'study support search' page, your MyAAT account details are authenticated first, before you are redirected to the 'Green Light' test dashboard.
If you do not, you will be prompted for a username and password intended for system administrators, not students, so you will not be able to log in.
Please let us know if you encounter any further issues.