To join a group, first make sure that you're logged in to your account. Click on the orange Navigation menu icon in the upper right-hand corner of your screen to access the Navigation menu.
Click on Groups.
A number of Groups will be displayed. When you've found a group you'd like to join, click on the name or picture for that group.
On the right side of your screen you'll see the Join option.
Click on Join. It will take just a moment. Once you're a group member, you'll see the messages posted by other members and be able to post comments. You'll be able to see your group membership in your notifications.
In some cases, when you click on Join you'll receive a "pending moderation" message.
In this case, the creator of this group has chosen to moderate who can join. They will receive a request from you to join their group. You will receive a notification when your request has been accepted or declined.