GB Hacks comes with a free 5-site license: Please visit the plugin page.
Log into your WordPress admin (i.e., your dashboard)
Go to Plugins->Add New
Go to Upload
Upload the gb-extras.zip file
Install and Activate the plugin
After activation, you can find the plugin's settings in the Dashboard under GenerateBlocks->Hacks.
Download the plugin zip file of the sales email you received
Unzip the plugin zip in a place you can remember for the next steps
Log into your FTP program of choice for your website
Upload the unzipped folder into wp-content/plugins
Log into your admin dashboard
Head to the plugins screen
Search for GB Extras.
Activate the plugin
After activation, you will be taken to the plugin's settings screen.