When adding the device to your App account, to enter the device mobile number, in the “Country and area” box, choose Spain +34 to add the international country code of the device mobile number and in the 2nd box manually add the remainder of the device mobile number. Tap next on the top of the screen.  If Next is not displayed, hide the keyboard and next will be shown.

Tap on Master 1 and Tap Done. You can Edit Master 1 to your own name in Device settings once device is set up.

Note: The first account connected to the device will become the device administrator. This can be changed later if you wish.