Yes, an appointment is required.
When you open your Groupon, it will include redemption instructions under the "How to use this" section.
To access your Groupon, please sign into your account at http://www.groupon.com. Once you are signed in, you will see your name at the top of the deal page. Put your cursor over your name and your account menu will drop down. Here you'll be able to find your Groupons in the section called "My Groupons".
You can view and print your Groupon by clicking the "Print" or "Print All" link and get all the information you need to properly redeem it.
Nov 2, 2011