Question

Can I have instructions on how to remove and fit a new Remis tilt and slide roof dome

Answer

The rooflight dome is screwed onto the hinged runners and assuming these runners are serviceable the removal and replacement of the dome depends on accessing the fixing screws.
Half of the fixing screws are accessible from inside the caravan but the front screws are only accessed with the rooflight open and then a 'stubby' cross head screwdriver is needed. This is not the easiest of jobs and you need to use the gap between the roof and the dome to get to the fixing screws.
I hope this is helpful.