To view your attendees, first go to the open days module on your admin area and select the 'View' button next to the event you would like to view.
You can view all the attendees of your open day from within the 'Attendees' tab of your event:
Your list of attendees can be printed if you select 'Print Documents' and exported if you select 'Export to CSV'.
Selecting 'Email Attendees' will bring up the below overlay:
Click 'Submit' to send the email.
All attendees of your open day events will also be listed on the contacts module of your admin area, with an open days tag.