The link to all admin is at the bottom of the page in small blue letters "Go to Administration"
You are the administrator, so you're the only one who can see it. When you click there, you'll see the admin menu on the left side.
Forum management: make new categories and forums
Forum permissions: decide if forums are visible to public or not
Group management: create a new group
Group permissions: decide if a group can see certain forums or not
Right now there are two groups:
- you yourself -> your group is the only one to see "My Diary"
- the web group (you and myself) -> this group the only one to see "Web Stuff"
These are two hidden groups - meaning other people cannot see that they exist - I mean the groups - the can see that these people exist.
Other people also cannot see the "categories" that these groups are in