The tracker itself isn't activated until you report your car as stolen so it doesn't provide any day-to-day tracking functionality. It's the associated OBD device, that is usually fitted along with the tracker, that provides the realtime tracking capability (via the Tracker smartphone app).
Assuming that Lexus have fitted this OBD device to your NX then the following post that I made on another, related, thread may help:-
https://www.lexusownersclub.co.uk/forum/topic/148784-lexus-tracker/#comment-1369827