You can find files in Overdrive using the Site Search (if your admin has enabled it from within Site Settings).
TIP: if you embed a document or file on a page and want it to be found via search, make sure you move it into the Site Folder.
Overdrive Site Search is similar to a search in Google Drive. A search for green red will find files that have titles/content with green and red, putting the words in " " will find files that have the phrase green red.
Overdrive also accepts Boolean search terms:
Once on the search results page you can use the Advanced Filter dropdown to filter results by