Here is a quick guide if you are looking to integrate WordPress and bbPress so that your WordPress users can log into bbPress and your bbPress users can log into WordPress.

1. Download/install/configure WordPress. You will need to upload the WordPress files to your web site directory and create a WordPress database. The installation process for WordPress is painless.
2. Download/install/configure bbPress. For the easiest and painless experience, upload the bbPress files into the same directory your WordPress files are in (most likely your web root folder).
3. Do not create a bbPress database, rather define use your WordPress database settings in the bbPress config.php file. At the bottom of the config.php file for bbPress there are preferences that you will need to set so that bbPress knows to share cookies and authentication. This is documented in the config.php file so just follow directions.

That is it. Once you have both bbPress and WordPress set up and configured, your users can then enjoy having accounts to log into both systems using the same user name and password.