Before you can Request an Abstract for your event, you must enable Abstracts in your event‘s settings. This can either be done during the Setup Wizard, or afterwards in Event Setup > Event Settings > Configure Tab
To enable Abstracts in your event after the Setup Wizard:
Navigate to Event Setup > Event Settings > Configure
Change Include Abstracts to Yes and Save
You will now see "Abstracts" appear in the Event setup box, and you can begin requesting abstracts.