How the Switches Make Contact
I made an error in the crash course about switch connections.
Most small switches connect contacts opposite from their position (if the switch is up, the bottom two contacts “connect”)
This wiring diagram explains this visually here:
A viewer broke apart a switch to show the mechanics:
Inside the lever is a small spring (not visible here) that pushes the small rod down. when the lever is switched, the small white plastic part glides on the switch plate which works like a teeter-totter and connects the middle contact to the opposite contact of the lever.
My apologies for the error, and I hope your circuits are not ruined!!