On the air conditioner you need buy a new seal the ac sits on rubber seal
This involves taking the cover off inside make sure you shut off the power to the ac
There should be four bolts and hooks to hold the ac too the roof you will need to unhook
The wiring takeoffthe four bolts once loose the ac can be lifted the gasket is rubber you can
Get a new one at the rv store these wear out over time
Dianne, can you take some photos of your roof and post them here?That might help ID the material its made of.
Looks like someone used a white roof coating on it.Now thats its there you are kinda stuck with it.I would scrape and clean it and just reapply a similar product.