Categories in a forum are used to group similar boards together which are what hold the topics and posts. These are vital to having an organized forum.
1) First, go to Admin.
2) Click Boards.
This page contains 3 tabs which can be used to manage your boards and categories. We'll start with Modify Boards, shown below.
Let's add a new board.
3) Choose a category the new board will be created in.
4) Set its position in the list.
5) Enter a name that will be displayed.
6) Type a description.
7) Select which member groups will be allowed to view this board.
Use this first set of options to restrict board access for non-administrator users. If you don't want to allow polls, choose the second option. The third option won't allow users to create new topics, and the last will let users view posts only.
To allow additional members to moderate this board, enter their usernames here. Note that you will not need to add administrators; they can moderate all boards automatically.
8) Deselect Count Posts if you don't want posts made in this board to count towards users' totals.
9) Click Add Board.
Use the same process to create as many boards as you need.
Now let's create a new category.
10) Specify where this category should appear in the forum.
11) Enter a name.
12) Then click Add Category.
Use this link if you need to modify a board.
13) Make any changes then click Modify.
That's it! You now know how to manage boards and categories in SMF.