It isn't as straightforward. You need a Samsung phone to pair and setup the app. does not pair with iPhone. Once setup, eSim can be enabled(recommend Sunrise/Swisscom/ other shops doing it for you)

I'll not recommend buying this watch for 4g/LTE usage. The battery is very poor, drains a full charge from 100% to 7% without any use. And above all Samsung service response is very poor. Rather buy an Apple Watch, am waiting for my return to be accepted.