Search Engines
Editing your search engines is very similar to customizing your configuration. To add a search engine, just select "Search Engine" from the [+] menu at the bottom left. To configure it, you need to find out the string before and after the search terms that the site in question uses. Do this by going to the site and searching for anything, then on the results page copy the text to the left of your search query. Then in Butler paste it into the URL prefix field for the engine you have created and selected. Then copy the text from the right of your query and paste it into the URL suffix field in Butler.
Does that sound complicated? Chances are you won't have edit your search engines at all. There are already quite a few search engines pre-installed.