HELP How do I download the mail addresses from participants pre-registration?

I got participants to pre-register for a webinar instead of simply giving them a link. I have 70 people in there who now need me to send them the event recording. I want a database to use in the organisation's mail chimp account.  How do I download their email addresses? ... I cannot find anywhere with instructions! very frustrated . Nobody in my business knows how to do this. 

thank you if you can share some insights that will help me

Gina