Yes, If you have Compression, fuel and spark the engine WILL Run.
Yes, on the left handlebar is the horn/kill switch. it should be able to turn.
You'll want to turn it clockwise, turning it couter clockwise kills power to the plug (sort of) You'll know if you have the ignition off when you are trying to start the moped as the horn will beep every second or two.
Helpful hints before trying to ride the bike.
Check the brakes, and make sure they work!!!!!!! Test the brakes on level ground, and then find a short incline to test. It's one thing to have brakes that work at 5 M.P.H, and not at 30+ M.P.H
Clean, Clean, Clean out the fuel tank!!!! If the bike has been sitting, you will need to do this.
Also, pull the fuel valve, (tank mounted on left side of bike) and clean it with carb cleaner. Pull off the airbox, and spray some carb cleaner in the throttle body. Try to get a little in the fuel jet (little brass thing in the middle of the air opening.)
Check hoses and belts, and drop in a new spark plug ( changing the plug on motobecanes is a pain in the ass at best.)
I just got my moped running the best it ever has and broke the drive belt at about 20 M.P.H Today. It sucked pedaling it back home (3 miles from where I was when the belt broke) My engine seems okay, and I'm glad I wasn't going full speed, as I may have damaged the engine if I was.
Check the speedometer, does it register when you pedal it?
How long has this bike been sitting?