Good timing as I asked something similar
here to make sure I understand
First thing to check is the propane, so let's focus on that...
I ASSuME:
you have both bottles filled and the valves open on both bottles ?
you have the auto-changeover regulator turned toward the open/filled bottle?
it make take a bit, but do turn on the cooktop and keep clicking until it starts... mine took at least a few minutes the first time...
keep a flame by the burner or clicking the starter continuously to limit the propane leaking into the rv....
good luck !