So I've been using Garmin Connect with one type of Garmin watch and now I've switched to another type of watch but I can not figure out how to make Garmin connect recognize the new watch to upload new data. Do I need to create a whole new account just for that new watch?
No. The different devices are on Garmin Express. In the top left corner there should be a photo of your current device with a drop-down list arrow. Click the arrow and there should be a plus sign with "Add New Device".
