Ok, you've got the right idea but some of your electrical troubleshooting is incorrect. To check a battery draw, you will not be checking for voltage. I'm not quite able to see your multimeter setting, I'm assuming you had it set to voltage. You SHOULD be getting voltage if you have a multimeter hooked up, completing the ground circuit
Parasitic draws are checked with the AMPS setting. Wikihow has a neat little article on the subject. Pay attention to which port your test lead is plugged into on the multimeter. Checking AMPS with the test lead plugged into the incorrect port of the multimeter can damage your meter. Refer to the users manuel or interweb for the correct port.
To check the ground cable: Multimeter set to ohms/resistance. Stick one test lead on the negative battery terminal ground cable. The other end on the chassis somewhere. The whole point of this is to measure the resistance where the ground cable bolts to the chassis. You should see a solid 1 ohm or so. If it spikes, you may not be making good contact with your test leads. Scrape and dig the lead tips into the testing surface to ensure solid contact. Still spiking? Fix your ground cable.
Disconnecting the battery while the engine is running can help diagnose some problems. Keep in mind, I have seen idling engines stall out even with a perfectly functioning charging system. For proper test execution, I suggest holding the engine at 2000 RPM.