When you first open Catfish, you are presented with the window shown in the example below:
The four main parts of the window are highlighted in the example:

1. The location selector
   • With Catfish, all searches are done relative to the directory chosen in the location selector. Using this button, you can choose a different directory, file system, or network location.
2. The search entry
   • Combined with the location selector, sidebar filters, and advanced search options, Catfish will find any files that match the pattern specified in this entry.
3. The gear menu
   • Less frequently used functionality is hidden behind the gear menu. From here, you can choose advanced search options, the preferred results view, toggle the sidebar, and update the search index.
4. The sidebar
   • The sidebar is not displayed by default, but enabled from the gear menu. The sidebar houses file type and modification date filters to narrow your search.