It´s a gadget to help feeding the filament in the enclosure of your 3D-Printer, when the extruder is far away from the spool (in X) it may happen that the filament tangles a bit.....not with this simple guide
Print with standard settings
0.4mm nozzle
0,2mm layer
then glue both parts together or as I did (not so well) heat them up and push them together.
PS: on the first print the clearance was to tight, I corrected this in the uploaded files.
The author hasn't provided the model origin yet.