The Forums link in the Secondary Navigation points to a page created by the bbPress plugin.
bbPress is optional and not required for Caroline to operate without forum features.
This is a large plugin with a many options and add on extensions available. The bbPress team has a large pool of documentation available to assist with set up. Because of this, we will not go into bbPress instruction in our forum.
You may use bbPress either on its own, or in conjunction with BuddyPress as we do in our theme demo.