To display the content for forums, bbPress relies on the theme templates. But, these are specialized template, and most themes don’t have them. So, how the bbPress uses templates?
bbPress Under the Hood: Theme Compatibility System
bbPress requires theme templates to display the forums content. Currently, bbPress needs total of 16 theme templates for all content types and taxonomies.
How to safely override and modify default bbPress templates?
There are many ways to modify the way the bbPress forums look like, styling changes, filters and actions and overriding the templates bbPress uses to render all the forums elements.