I believe the "ignition power transistor" is the component the ECU switches to turn coil primary on/off. It should be about 1 inch x 1 inch flat black near the coil(s). A transistor is just a switch.

I don't know the specific instructions you're reading but an analog meter sweep needle will show the voltage switch must faster than a digital meter.

Your trying to see the primary coil voltage go from the spec'd amount (12 maybe) to zero and back, over and over as the engine cranks.

And/or trying to see the signal voltage from the ECU (5 volts) go on/off.

Depends which connection you're testing.