How do I autotag movies once they're already in my library?

Okay. So I've got a bunch of movies in my library that have no tags/info other than their name. In theory, it should be a piece of cake to look them all up on Amazon and add all the rest of the info (just like you do when you click the "+" icon, enter a movie and click "Find Movie"). Except I can't find this feature anywhere.

How do I convert a huge list of movie titles in my library into proper entries?
Essentially, I'm looking for a bulk "Find by Title" function.

Any help much appreciated.