The module is rather simple. It utilizes Google's built in styles, so you can choose from 4 preset sizes - 15px tall, 20px, the standard 24px, and a tall 60px tall button. The buttons all update using AJAX so there is no page reload and the count is updated in real time. Pages you have +1'd will show the button in blue to indicate you have already clicked. You do have to be logged in to your Google account in order to submit your clicks.
Installation is very straight forward. Simply visit the JED and navigate to the BNR Plus One page to download the latest version. Then log in to your Joomla admin and go to Extensions > Instal/Uninstall. Select the package you downloaded and let Joomla do the rest. The module will work in any visible module position and it supports the use of module class suffix so you can style it to fix your needs. Select from the 4 size options and whether you want the count to display along with the button. Note that the large 60px button displays the count by default so the module option will not affect the count display on that size if you select it. That's it, instant +1 goodness, just add clicks!
If you use BNR Plus One please be sure to visit the JED and rate and review our work. We welcome all feedback and do our best to accomodate suggestions and bug fixes.