For those of you trying to set up your Apple Watch 3 LTE with ATT, beware. ATT has no idea how to do it. The answer, after an hour at the store, is to make them load your watch’s EID number on the bottom of the watch. They will tell you at first their system doesn’t take that number, but it does. After they loaded my EID number, it all went smoothly. You may have to restart the watch and the iphone, but it works. ATT online tells you all the wrong stuff—you need a new SIM card—but the sim is electronic, not physical. So, I hope you all can avoid what I went through.