no prob. There are some funny stories of some very accomplished organists and their very 1st experiences with the organ because of this very reason.
One thing you want to avoid, is after the organ is on, don't push in the left switch again. It's kind of like trying to start a car when it's already started. Also, when you turn it off, don't turn it back on right away. These Hammonds are not purely electrical, like your synths, they are electro/mechanical, there are moving parts in there like a motor.
Make sure that people that play your or your churches organ understand this.
I like the double switch because it keeps people off of it that shouldn't be on it.