Dometic roof are motor shot. How easy to replace?

After reading this thread again I see people telling me to try to swap out my "Run Capacitor" and some telling me to swap out the "Start Capacitor". Which one is it? And it seems like I read somewhere that you need to drain the energy out of the capacitor before you swap it out. How do you do this. Thanks everyone for your help on this. But happy to be learning.