Installation should be pretty easy - just navigate to the spanghurt.user.js file and click the [Raw] link.
NOTE: If you do not have Greasemonkey 0.9 or higher installed, you will need to temporarily disable Greasemonkey when you click the filename as it will attempt to install the webpage rather than the "Raw" script.
When you first run the script, you should be presented with the initial installation message and a few questions - answering these now will mean that you do not need to view a large number of pages and wait for the script to detect everything automatically.