If we select a simple mask such as AlbumArtistorArtist/Album/Track - Title in the dropdown and then Edit we see
The AlbumArtistorArtist/Album/Track - Title part is just the name of the mask, it could be anything but clearly makes sense to try and describe what the mask does with a sensible name.
The Example field changes to reflect how the mask would affect the filename of an example file
The Mask Fields lists all the metadata fields that can be used in the mask
We explain this mask in more detail in the next tutorial.