This task may be easier with the door removed from the appliance and laid horizontally on a work-bench.
To replace the door glass:
i) Two stainless steel strips hold the glass in place. Remove the four M4 size Phillips head screws from the stainless steel strips.
ii) Take out the glass, and check if the grey rope beneath needs replacing. If so replace this rope as well.
iii) Position the new glass on top of the grey rope and re-fit the stainless steel strips and M4 screws.
iv) Take extra care not to over-tighten the screws, otherwise the glass will crack when the heater gets hot and the door expands.
v) On occasion, the M4 screws will have deteriorated from the constant heat in the firebox resulting in them snapping off when trying to loosen them. In this case, a new hole can be drilled in the door and tapped using a 3.4mm drill bit, and M4 tap.