Follow the link in the email you receive inviting you to become an Account Administrator.

Register for an Oxford Abstracts account or log in if you already have an account.

When you log into the Oxford Abstracts home page, your first screen is your personal dashboard, which will show you what roles you have and what functions that you have permission to perform.  If you have been set up as an Account Administrator, you will see a list of accounts you are an Administrator for in the 'Accounts' section.  

Click on the client name to view/edit their account and events.