This schematic shows you how to crank your engine bypassing all the internal wiring. Or if you have no wiring for whatever reason. If you are not sure how long it's been since the last time the engine ran. Take the extra time and prep the engine before first initial crank.

1) Please wear safety gear: IE, Gloves, goggles or a face shield during this process and have a fire extinguisher near by.
2) Remove each spark plug individually and inject oil into each chamber and place back the spark plug after doing so, as to not get them mixed up. 
    A oil change is a good idea, this can be done prior or after the initial crank, this is solely up to you. If you want to make sure it will turn before you potentially 
    waist your oil.
3) Make sure you have a good/new Starter and ignition switch (Part Numbers shown)
4) Have a small gas can with the highest octane available (not diesal) and place some fuel directly into the carburator. Caution: Fuel spillage will ignite and start a fire.

Wipe off any spilled fuel with a clean dry rag. Especially from your hands or body.

I hope this helps you out, good luck and most important BE SAFE!