Remove the wire reel.
Remove the top roller with an allen key.
Remove the plastic cone the wire runs through..torx screwdriver (red arrow).
Undo the nut holding the liner (blue arrow)...10mm while holding the bigger nut..17mm.
Remove the liner.
There will be an o-ring on the liner that needs to go back on if the new liner doesn't have one.
Remove the tip and gas diffuser and fit liner...trim to length and refit bits.
Put all the bits back on.