Here's a helpful beginner's guide that includes a few handy keywords, how to create custom searches and other features available to users of the free version:
https://www.alfredapp.com/blog/tips-and-tricks/beginners-guide-to-alfred-searching-your-mac-and-the-web/
With the Powerpack, your options open vastly as you could then create file filters to search for particular file types or in only certain directories on your Mac, making search even more fun!
