Sorting of files is controlled by sort mode, which may be configured in Configuration, or in popup window invoked on Sort by button.
Various file types are affected by different configuration.
A) Default sort mode of files.
This applies to all files, except of images/video/audio files if they are configured to be sorted differently.
The sorting is set to one of four modes, and can be optionally reversed.
B) Optional sorting of images, videos and PDF.
If set to Default, then media files (those with thumbnails) are sorted by mode A), otherwise they are sorted by their last modify date, either older first or newer first.
C) Optional sorting of audio files.
When checked, audio files are sorted by their metadata – artist, album, track number, title (if the file contains these). When not checked, audio files are sorted by mode A).
D) Sorting of folders.
Folders are never sorted by mode A). Folder are always placed before files, and they are sorted by one of three modes.