hello, I just put together my forum, and I wanted to know how to make the width smaller, as well as in wpforo.
That's should be done from your theme side. This page layout is under your Theme control. wpForo only controls the inside layout and style. You should edit the forum page and search for theme layout settings in Edit Page screen. If those don't allow you to change page layout, you should insert custom CSS. We can help with custom CSS, just leave some URL to your forum page.