Nilo,
First starting, (not being a smart a** here) read the instructions that came with the engine. THEN, if it won't go, finger over carb, or muffler (it will do the same thing), and watch for fuel to go through the line to the carb, 3-4 flips should do it. Give it a couple more without the finger, and without the glow igniter. Then open the throttle 'til you see a little opening in the carb, (1/8th of the total opening should do) hook up your heat, and hit it with the starter. It should go. I have one of these, and it's been a good engine.
If you are over priming, it will backfire, or kick, and if you are under priming, it will just grind for awhile, then catch.
Keep asking, that's what the begginers forum is for!!
As for stopping, two thing you can do, 1. cut the throttle, and trim all the wa- it should quit. 2. Pull the fuel line. 3. in case all else fails, throw a rag into the prop.

Jetts