Stimulus_Reflex Demo's - Populating Dropdowns from tables
So, I've spent about two days on this, Googling, watching many, many YouTube videos. So much that I'm on information overload - and obviously missing something. I've worked through the Stimulus.js demos on their page. What I'm looking for is simple - if you look at their demo page - the geo_tracker does what I want - select a region - that populates the and shows the next dropdown of countries. I've been through their code, but can't quite figure it out. I think what I want to do would be well suited for Stimulus_reflex. But I can't seem to find the right article, or the right demo, or the right video (and yes, I subscribe to gorails but the demos don't qquite do what I want).
Am I on the right track, or is there an easier way to do this? If it is the right track - can you point me to the tutorial I need to follow, the YouTube video I need to watch, or the article I need to read?
Any help is appreciated.