Couple of Newbie Heater Questions

[rec]

...Hi! We are using the heater for the first time ever in our newly aquired '89 Airstream Excella. Having lived a mechanically sheltered existence, we've never actually dealt with maintaining gas appliances before - and the manual is that annoying type that just assumes you know your way around this stuff, so I have a few questions (don't worry - we're smart enough not to move this thing until we understand how to use the propane tanks properly)

1. In order to turn the furnace on, it says you have to turn the "Manual Lever" off and let the blower run for five minutes to clear the air out. Fine. But WHERE is this manual level? The instructions refer to an illustration that doesn't exist, and the text says it should be near the furnace body, but I SWEAR I don't see any level on the furnace. Are they referring to the connections at the eternal tanks themselves?

2. For that matter, here's a really stupid question: How can I tell if the external tanks are ready to be used? I mean, the tubes are connected properly, but do I have to do something to them first? Should the levers/dials be turned on all the way? Half way? On only when I use an gas item? On all the time? Off when we travel? Does twisting the levers clockwise open or close them? This is the sort of context that instruction manuals never do a good job communicating...

I know these are annoyingly vague questions, but I really don't know where to start here. I'd love some advice on where to go to learn more...

Thanks!