Re: Let’s start at the beginning!
bbPress is NOT a plugin, it’s a separate application that can be integrated with WordPress.
If you want to integrate bbPress and WordPress, note that if you are using WP 2.6+, you must use the ALPHA build of bbPress. During your install process, you will be asked about server settings. Tell bbPress to point to the same DB you used for WordPress (don’t worry, it won’t overwrite anything, but do make a backup anyway to be safe).
The Basic Integration Screencast should help you some.