You’re going to half to separate the two shell halves to get to the motor terminals and the leads from the trucks by the looks of it.
How brave are you feeling?
Current is measured in Amps (A), not volts. And you need to make sure you have your probes put in the current measuring plugs. It should be plugged in series with your DC throttle.
DC Throttle + terminal to Amp Meter + probe
Amp meter - probe to track A terminal.
Track B terminal to DC Throttle - terminal.
Look at your Photo Bucket site again. Use the IMG link so the picture shows up immediately.
In the link I provide before are the instructions for using your meter to measure current.
Rich