Unlock the extruder, pull out the filament and Teflon tubes.
Completely remove the filament from the Teflon tube (waste).
Restore the Teflon tube and unlock the extrusion.
Insert filaments until they are coming out from the Teflon tube, and lock the extrusion switch until it cannot be pushed
Click Extrude on the screen, observe the nozzle, if the filaments have been extruded, wait for "Extruding finish", if they are not extruded, lightly push the filaments forward and click "Extrude", and clean the nozzle after Finishing extruding
