I bought the Groupon and took my first class 2 weeks ago. I had no difficulty signing up by following the directions on both the groupon and the website, but i did hear a few people thanking the instructor for helping them to sign up.
I am not a physically fit person, nor am i flexible in any way. I was able to follow our incredibly friendly and energetic instructor without any problems! She corrected us if we were lost, and offered easy to harder options for nearly every workout. If i had to stop or take a break, i didn't feel bad for it.
My second class had the same wonderfully friendly atmosphere. It did move a bit faster, but Marnie was still wonderful with us newbies (and there were a few of us! )
I plan to bring many friends this month as well as buy more classes. It's quite a fun option for fitness and I'm excited to get flexible and strong with their help!