In order to protect the hotend cables and ensure proper orientation, it is highly recommended to use a box. Use the one provided in the kit.
⬢Place the Extruder-body with the hotend on the box and make sure the cables are pointing down.
⬢Place your finger temporarily on the longer magnet and place the extruder motor assembly on the Extruder-body. The Bondtech gear might pull the magnet out while assembling parts together.
⬢Make sure both parts are aligned.
⬢Place the Extruder-cover on the Extruder-body. Again, make sure parts are properly aligned.
⬢Insert two M3x40 screws, you've prepared earlier. Tighten them, but be careful, they are slightly longer, than the thickness of the entire assembly.
Place the extruder aside for few steps, we need to prepare another part. Leave it on the box to prevent damaging the cables.