I always like to get info off YouTube.
In that video, we have a guy who is replacing an engine because the old one blows head gaskets and he can't figure out why. Then he shows you how to start it, while using 18 gauge wires. That'a less than half the size they need to be. Although he does have everything hooked up correctly and it did start the motor, the maker of the video is prime reason why I hate the internet and YouTube. Because anyone with a camera can post a vid. The blind leading the people who can't see.
I suggest hanging out here and getting advice from people who actually know how to fix a Cub.