In order to correctly install the plugins you desire you can copy the files into your [firefox/mozilla]/searchplugins/ directory. For windows user that's generally: C:\Program Files\Mozilla Firefox\searchplugins\ if you're using Firefox
Or far more conveniently you can click on the links below:
Install Gutenberg (Authors) Plugin
Install Gutenberg (Titles) Plugin
Install NUIGalway Library Plugin
Install NUIGalway Exampapers Plugin