Get the support ring and the new power plug from the Retro Fit Kit (your ring may appear different or different color).

Place the ring over the 4 pin connector remaining on the hotend board as shown in Pic 2. This will be a tight fit but should slide over the 4 pin.

Insert the new power plug into the other side of the retaining ring of the Retro Fit Kit, and insert the legs of the plug through the now-cleaned soldering holes on the board.

Take note which side the clip is on for the plug you are adding. Polarity is IMPORTANT so it must be inserted as shown in Pic 3!