Just go to: OPTIONS > STRUCTURE > CREATE NEW SUB-FORUM.
You can then customise it in the same way that you can your top-level forum, using the various options on
OPTIONS > APPLICATION
and
OPTIONS > USERS
Be aware that sub-forums inherit the appearance of parent forums. User permissions are also inherited unless over ridden with permissions applied at the sub-forum level.
If you have a specific question, just ask. (The documentation can be a little behind the current product, so it's always best to ask if you can't work something out.)
Volunteer Helper - but recommending that users move off the platform!
Once the admin for GregHelp now deleted.