Install plugin + Grimlock addon
First you need to download, install and activate the plugin.
After the installation/activation of these two plugins, you can go with basic setup. It’s pretty simple. You just have to create a new sidebar area for replace the sidebar of your choice by a new one (to inject bbPress specific widgets). Watch the video below to see how.
If you want more information on how to create and managing widgets area, you can read this article.
To go further with visual customization you can read these articles.