Note you will need a user account to view the issue.
I thought I had set it so that sub-forums would be listed under the particular main sub forum. But they are not listed. The user will only know about these two sub forums if then click on the main sub forum.
I found some links about this with custom code but I don’t know how reliable that is because someone spoke about getting a white screen.
I think I would be happy just to have some kind of symbol next to the forum to indicate it has sub-forums. That would be less code requirement and might be able to be part of bbp style pack as an option?