Once again I can't get Jekyll to work on a Mac

I’ve tried a couple of different times over the years to install Jekyll on Macs, but I can never get it to run. The various online support cures are not effective and, honestly, it’s not worth the effort if I can’t get it to work correctly on install. I’m not confident I won’t run into future problems. But, I’ve had good luck using it on GitHub, so that’s what I’m doing for now.