Point at or tap any part to name it. Tap a wire or metal part to test it.
Glow shows volts to ground. Amber dots are lamp current; red is current through the person, hidden under 1 mA.
A switch goes on the hot, never the neutral, 406.30(B).
The white goes to the screw shell, 410.90. Swapping them reverses polarity, 200.11.
Test before you touch, every time (trade practice). A switch in the off position is not proof.
"No reading" means the part connects to nothing. That is not dead: a bulb or a fault can make it live. A digital meter can show a ghost voltage there, sometimes tens of volts; check the meter on a known live point before and after (trade practice).
14 AWG copper on a 15 A breaker, 240.4(D)(4). 40 ft to the switch and 15 ft to the light at 3.07 Ω per 1,000 ft, Chapter 9, Table 8.
60 W bulb, drawn as a fixed 240 Ω, its resistance when lit. Cold, it is lower, so the real shock is a little larger.
The other hand is on a metal water pipe, bonded at the service, 250.104(A)(1). Only the hand-to-hand path is counted.
Skin: 1 kΩ wet to 200 kΩ dry, hand to hand. Shock effects are typical OSHA figures, not code. Dry skin today can be sweat or a cut tomorrow.
The panel is fed from the service, not drawn, where neutral and ground are bonded. This is an unfinished basement; many rooms also need AFCI, 210.12(B).