Is there a menu I need to access in the watch to initiate the download and install? How exactly do I update the firmware to the latest stable (non-beta) build?
For production firmware, it will come OTA (BT can take a longggggg time), or as was said, you can use Garmin Express. For beta FW, it's a manual process where you have to download it and copy the fie(s) to your watch.
Another thing to note if you have an APAC (Asian-Pacific) device, they use different firmware than rest of world devices.
what are the differences between APAC and Rest Of The World versions? Language pack? or features? Leaving in APAC area what's the impact to Load APAC Beta on US version?