How can I join groups?

To join a group, go to “Find” at the bottom of your toolbar and then select the “Groups” button at the top. Under each group you will see “Join”, just click on it and off you go. However, if it is a private group, you will have to wait until the group owner allows you to join. Bear in mind that the group owner himself decides who he grants access to and what criteria you have to fulfill in order to join the group.

A little tip: Read the group description through to the end so that you don't get kicked out straight away for breaking the rules.