A Grace group is basically just a small group (no more than 4 to 6 participants not including 2 leaders) that works through the Journey Guide (kinda like a really BIG workbook) together.
There's an expectation of privacy (what's shared in group stays in group), and there's work to do every week.
It's a 12 week (12 Chapters in the book) program. A Scan of Chapter 10 is in the thread above. You can find more information from the producers of the material at: www.ohmin.org
I think they also have a place to look for finding a local group (typically Grace Groups are face to face) and also have a number to call where they can try to give you some local contacts.
I'm currently working toward trying to get an online group going, but have quite a few logistics and even the need for a co-leader in order to get it off the ground.
Hopefully soon, but finding and training a Co-Leader is my biggest hurdle right now.