Remove the two screws behind the dock connector, fully disengage the tray and the plastic around the dock connector should pull out into the gap between the connector and the tray and lift it up.
Now take the front of the box off, the top part of the dock is one piece and with the two screws gone should slide towards the front and then can be lifted out, be careful of the flat flex cable going to the lock detect PCB.
Remove the support brace running along the unit and remove the main PCB, this should expose the clips for the plastic cover on the side, unclip these and slide it towards the front of the case to expose the screws for the fan.