Safari Reading List not syncing

I am a mobile app dev, so asking something as basic as this is a tad embarrassing, but I just don't seem to understand what I need to do to have my Reading List sync between my Apple devices. I have the sync over Wi-Fi setup on each device, have done this while cabled to my MacBook pro, done a sync, am powered, on the same Wifi, even prayed to the moon, but no syncing being done. I have searched for a clear set of instructions, but with Apple changing the layout of Settings so often, all I have found are hopelessly out-of-date. Pointers, tips, incantations are welcome! thanks.