This is a three parts tutorial video series that shows all you need to know about switches. Part 1 explains the basic schematic symbol of switches , how they are identified and used in electronic or electrical circuits and how to test them.
Switches :
Part 1 : Switches Explained
Part 2 : Switch with Pilot Light
https://youtu.be/Bnm8TNMZ2-Q
Part 3 : Selector Switches
https://youtu.be/cyf9cqVM3KU