To install and use scripts, you first need to install either tampermonkey or violentmonkey. Greasemonkey may or may not work.
In order to install a script, click on any link in the list above that ends with *.user.js.
it will take you to a page with script's source code. On that page in the top right corner, click on the Raw button.
Tampermonkey/Violentmonkey will then prompt you to confirm the installation.
After installing (or updating) a script, you need to reload all vola tabs.
You may something have to reload tabs when you first start your browser and your previous session is restored. This is particularly true for Chrome.
Check the Wiki for descriptions of some of the scripts. Stuff's work in progress tho!