Insert one end of the PTFE tubing to the extruder.

Insert the other end into the Hotend.

Make sure that it is fed all the way to the bottom of the hotend, this should be approximately 6CM.

Double check, as running filament through the hotend with the PTFE tube not all the way down will clog the Hotend.

If your hotend does get clogged you will have to disassemble it to remove the clogged plastic from the hotend throat.