Welcome to the General Discussion Forum. This is an open forum where anyone can post messages, and probably where most of the activity will occur in your community.
You might notice the login link on this forum's main page - it will either appear with your login name or the text "Not logged in". When you're logged in (depending on your privileges in the community) you might have the ability to edit the forum, edit and delete messages, etc. If you're not logged in, you can either log into your account, or you can create a new account. Registering for an account gives you additional features, such as the ability to have your own signature, or to upload photos and images.