Hi Krista -
Since imports do require an item in the Admission Item field, more than likely all that you need is "Event Registration" (without the quotes) in that field, unless you have some other type of admission item, like a "Sponsorship Package" or something specific to your event.
Here's an article that also helps explain a little more about Admission Items:
https://support.cvent.com/s/communityarticle/Creating-Admission-Items?is_article=true&lang=en_US&searchFor=admission%20items
Hope this helps!
------------------------------
Rebecca Yousif
Senior Administrator - Event Technology
------------------------------