Position the hotend on the hotened PCB as shown in pic1. The fan will be under the 10 pin connector, and the wires for the thermistor and heater will be on the side with the green connector and 2 white connectors.

The heater block should be in line with the part of the PCB with the words silk screened on them, with the heater screw being on the side under the electronic components for the pcb.

On the PTFE tube, one side is tapered. This is the side that goes in the knurled finger screw and should be towards the top of the hot end.

Holding the hotend to the pcb, flip it over and insert the PTFE tube and knurled finger screw into the hotend. Tighten this down with your fingers until it us JUST SNUG.

When you feel the knurled screw get snug, give it about 1/4 turn beyond snug ONLY, DO NOT OVERTIGHTEN!

with the knurled part snug, you can spin the collar of that section down to meet the PCB and tighten the assembly in place. This collar can be tightened securely and it will hold the whole assembly in place.