You will notcie in the top left corner, the current members of the group.

On the cork board you will see current discusions.

before you join the group you will be able to see the discussions, but you will not be able to participate in them.

To participate in the discussion, you must be loged on, and you must join the group. to joint the group, press the button on the top right corner "Join Group". The button will change to "Leave Group", and your name will apper in the member list:

to leave the group, just press "leave group" button.

To see and participate in a discussion, press on one the desired discussion.

To see members details you can press members list, or press on each member avatar.

The "Discussion list"  button allow you to see all discussion in a list format, and filter discussion by several options.