You will need to remove the cooling tube and the nozzle. Disconnect the connections to the aluminum block.

Measure the needed PTFE, then cut with sharp knife.

Insert the PTFE into the nozzle, then screw the nozzle into the aluminum block.

Now screw in the aluminum "cooling tower" with filament through the PTFE and cooling tower assembly for support and guidance.

Test that the filament END can be inserted and removed from the cooling tower without ANY resistance. If you feel resistance, unscrew the cooling tower and re-seat the PTFE.

The PTFE is not pressed in and can only be inserted into the cooling tower ONE-WAY.