@Arvid1: Do you have the LTE variant of the watch, and have you activated your network? If not, head to the Wearables app on your phone > Mobile Networks and follow the on screen prompts. Once activated, simply head to Apps > Phone on your watch to make calls without the need for your phone.
It was not possible to use my Watch 3 with my network (Telenor). nor has the ECG been activated in Norway.
I returned my Watch3 (Promised more than it dellivered)