To make your email eligible for testing, you will need to add it to a "Template" through the Dashboard.
Please follow these steps to do so:
Click on 'Templates'
Select a template (or create a new one)
'Invite' your card to the dashboard by typing in the email address that you want to make eligible for testing
Check your email inbox to accept the invite
Once you have followed the instructions in the "Invite" email, your email address will become eligible for testing.