Try squeezing "gently" on each side of the plastic cover facing the front of the car. The rear cover should come off easy. then slide the part with the red lens in it forward and that should come off easy as well. then look for screws mounting the light itself to the decklid and remove them, disconnect wire and thats it
Remember be careful with the plastic housing as they dry out and break very easy.
Good Luck and I hope this helps