As the 100th is not till March 28th, this group remains private till then. What that means is that new posts will not be displayed in the box on the frontpage, but you can see all when you visit. To enable commenting you need to be invited as a member. It is possible to apply for membership during the "private" period, and when we go public all can make new topics and comment on posts.
You may want to tag your work with AM100 or ITAF100 to be searchable in database under these two terms.
Have fun!