Hi,
the tutorial is ok for someone not knowing anything about electricity, but has one really big mistake in the #3 section ("short to power").
Referring to his picture both bulbs will always light up together if either switch is on because both switches will close the circuit for bot bulbs independably. You need to turn off both switches in order to turn off the lights (open the circuit). His statement "Thus, bulb2 will turn on along with bulb1, even when bulb1’s switch is off." is only correct, when in this situation bulb 2's switch is on.
Helmut
