OK, I’m giving up on the ProTrinket solution. I went with the ProTrinket originally because there was a wiring diagram I could understand (not a hardware person). I need a similar picture for the Mayfly. I don’t understand what the following means: “First you need to enable the pullup resistor on pin D10, which is already built in to the Mayfly board, you just have to close jumper SJ12 on the back of the Mayfly.”
I see the SJ12 D10 P/U on the back of the Mayfly. Don’t know what to do.