Unplug all AMS units and power on the printer to verify that it reports there are no AMS units connected. Turn the printer off, connect the AMS that you want to be number one then power the printer on again. Once it’s found the AMS (I don’t know if it’s instant or if it takes awhile) connect the remaining AMS units in the order that you want them to be listed. https://wiki.bambulab.com/en/x1/manual/Connect-AMS-Hub-and-multi-AMS
I’ve tried doing this in every possible combination, including powering the printer on and off between connecting AMS units. No matter what I do, the printer always shows the second AMS unit that I connect as the first AMS on the printer. When I connect the third AMS unit, it shows it as the third AMS. I don’t have a fourth to try yet. Has anyone figured this out?