Ok for rooftop air conditioners generaly one manual covers multiple models So.
Dometic rooftop air conditioner manual... that was my google search
Click here Odds are that's the right one but if you can get the model you can go to the dometic manual archive for an even better look.
To find model number method one
Remove lower grill and look up you may find a sticker showing the model. size and power needs
Method 2: up on the roof. Remove the shroud (you need to do this for cleaning anyway) clean the condenser (Fan side) while up there. again you may find the sticker.
Hopefully still readable.
Was the result