basically its a single screen dry sift. trichome size is 40 microns or less
Silk screens come in a variety of mesh sizes
Conversion chart
https://www.icmag.com/ic/showthread.php?t=215148
So basically you can see from the videos someone working (what should be bone dry) plant matter over a silkscreen right? The trichombs are falling through the mesh. you then collect and press the remains. voila , hash!
I think most consider 65 micron screen ideal