Lift external composite kerb onto the flat roof and fix together at the corners with screws.
Once the external kerbs have been secured to the flat roof cover the kerbs with weatherproof membrane.
Before lifting the glazed rooflight onto the kerb structure, run a silicone seal on top of the kerb membrane
Once in place, screw through the rooflight outer frame into the kerb at 250mm centres. Make sure fixings are all secure.
After roof has been permanently secured, fix internal plasterboard into U channel slot on the internal perimeter of the rooflight.
Clip on the interior trims - fix the two tight trims first and the other adjacent trims between the fitted trims.
Fix the exterior trims around the perimeter of the rooflight using a rubber hammer if neccessary.