hangnef

The documentation says to do this to load all samples in a folder into a kit

To quickly import all audio files within a folder, create a new kit as above,
but when selecting your file, press and hold down on the select knob. You can do
this either while “looking at” one of the files within the folder, or the
folder’s name itself. A context menu will appear, with options you may select
from by turning the select knob. Select the “ALL” option by pressing down on the
select knob again.

When I do this in the folder where all my samples are, I just see "CANT" on the LCD screen.

Do the samples have to be named in any specific way for this to work?

Yes please!