The engine won't start

1. Spark plug: it is a 3-prong spark plug that comes with the kit.
2. Black oil: it shows at the center of the picture where at the left corner of the engine head. The kit I have is the one I bought from Bikeberry.
Do yourself a favor and get a new head gasket and 4 regular nuts and lock washers for your head studs. Throw those acorn nuts away, half the time they bottom out before they tighten down the head, That's why you see oil at the corner of the head, it comes out from along the studs and runs down there. If you leaned your bike on the other side, that's where the oil would be.