In short, what is a qualified type and how is it used? (Any examples
would be appreciated.)

I feel somewhat embarrassed asking, as I used to know. I dropped Haskell
a while ago and am just now picking it up again, and unfortunately I
have forgotten many concepts.

If someone could point me to the appropriate tutorial that might be
enough. For some reason, all my StartPage searches are only bringing me
to documents that assume I already understand qualified types, or to
books I can't afford to buy.