I attend an agnostic AA meeting weekly.
There is an opening and closing statement read by a moderator. I can't remember the precise language, I'll try to get it this week and bring it back to the forum. It is mentioned in our opening statement that members may feel free to express their religious beliefs, or their absence or rejection of religious beliefs.
Between the opening and closing statement, people from the group share. The moderator tries to come up with a topic each week, but sometimes the group is encouraged to talk about anything they want. At some point a basket is passed, as there is a charge to use the building from 7:30 to 8:30 PM once a week, and the donations from individual members pay for that. There is coffee but no food, there are reading materials such as pamphlets, interpretations of the 12 steps from different perspectives (such as atheist agnostic and pagan), and the moderator usually brings a stack of books about recovery.
There is no prayer or meditation.
My group is small, sometimes only three or four people show up. When that happens, we sometimes skip the formalities and just sit around talking.
I believe that interacting with people who are struggling with the problem of alcohol or drugs provides very helpful support in the recovery process.