MyBB Community Forums

I am having trouble organaizing my forums. I dont know how to create categories (example, a category in this site should be "Custumization", where we can find "Code Modifications" and "Templates, Theme Sets and Graphics" forums.)
Can someone tell me how to make them, please?

You need to use the same form that you use to create a forum. When creating it, set the "Act as Forum?" option to "No."