I've attended Sexaholics Anonymous which is the same thing. Both are 12 step programes. If you aren't familiar, you can simply Google it. Don't let the words "God" or "Higher Power" put you off if you aren't religious. Trust me on this one.
The groups start with an intro from the group leader welcoming everyone to the meeting, read from a script and then several other people will read from a script each around a page long covering things like "What is an addict?" "Why are we here?" etc.
There will then either be a book reading from the main text from which the programme is based, a main share from another member about there story, or straight to the shares.
For the shares the room will go silent, and everyone is invited to share. This silence may last a few seconds, or afew short minutes. The individual shares, and again the room will go silent. This process will continue until the end of the meeting. The group leader will then close the meeting and people will chat and exchange numbers there after.
The new comer is the most important person in any meeting, and you will be made to feel extremely comfortable.
Even if you are having doubts at this stage for whatever reason, I encourage you to at least try it once before you dismiss it.
Hope this helps.