Engine died during break-in

I just had my engine start up and die. After hours of chasing wires and changing out the ecu,ballast resistor and the Coil. I finally figured out I had my rpm tachometer wire grounding out and causing my engine not to fire up. Make sure your getting power to the coil with a multimeter.
I have a cheap multimeter but don't know how to do this. Do you put neg meter lead on neg coil side and pos to pos side? If not please tell exactly how to do this. Very dumb about electrical. Thanks