Token is obtained automatically on granting the permission and refrehed on wallet start - user is not involved in it. If it fails to do so, it means that the device has no Play services installed / available.

I've released yesterday a small fix that will fallback to websocket nwc connection in that case (permission granted and device token missing).

Unfortunately this is really a "demo" solution as it will work only when app is in the foreground (means zaps are sent from app on other device / pc).