You need to start by defining a forum Group. You will find the Create New Group menu item in the Forum section of the Simple:Press admin.
In Simple:Press, a group is a container for one or more forums. There must always be at least one Group.
Think of it as a way of organizing and structuring your overall forum. In most respects, it has a similar role to the categories you probably use in your blog – a way of grouping items that have a common thread.
You can create as many groups as you wish but plan these and the forums they will contain out first to save later reorganising.
When you create a new group, you can give it a name and a brief description. You may also provide each Group with a unique, custom icon and a special message to display between the Group heading and the forum list below it.
You must also select it’s display position from the options provided in relation to the other Groups.
Note that the User Groups and the assigned Permission Sets selected for a Group will then be inherited by each Forum in the Group although these can be adjusted at Forum level.
After the group is created you may edit any of the above data. In addition, an RSS feed for the group will be created which you can optionally redirect to a feed service such as FeedBurner. By default Group RSS feeds encompass all of the posts in all of the forums belonging to a group although individual forums can be excluded.