If you are in your catalog, you can search within that catalog by typing text into the search bar.
If you'd like advanced search options, click the icon in the search bar.
The advanced options for the Songs tab and the Files tab have different options.
Song advanced options.
Recordings advanced options
File advanced options.
Another feature of the advanced options is the option to change your search from searching the current playlist to searching your entire catalog. Click the Search everywhere icon in the bottom left of the advanced options to apply your search to the entire catalog.