When you view the Group Discussions page, you will see something like this at the bottom. Remember, ANYONE may read the comments and discussions without having a Google email ID or belonging to our discussion group. If that's all you want to do, then you're all set to go...

If you want to sign in, make sure that #1 this is our group. Then #2 if you are already a member, just sign in to the group discussion area with your existing ID and password, or #3 apply to join the group.

To sign in, enter your existing Google email ID and password. You may then add to the discussion and comments.

If you don't already have a Google email ID, you can get one on the spot -- and then go back and Apply for group membership.