How do I send email to my event RSVPs

I want to send an automatic confirmation email message to attendees who have RSVP'd to an event. I can't find a way to do it even though I've activated the plug-in. Or maybe the plug-in isn't working because nobody is receiving anything.

Also, if I wanted to send a non-automated note to a specific number of members who have RSVPd to an event, how do I do that.

Thanks!
marcelino