To get the best out of Smartphone Link app and to be able to send addresses and locations from Android Google Maps, you need to install [Only registered and activated users can see links. ] in countries that Google Navigation is not enabled yet.

After you find a location with Maps, you press Directions button and as you press the Navigation button, a popup window appears, you select Smartphone Link and the location is send to your Nuvi and saved in Recent (Nuvi and phone connected).
Even if you don't have your Nuvi with you, you can temporary save a location in Smartphone Link app from Maps and the next time your Nuvi is connected to Smartphone Link, this location is transferred to your Nuvi.

Your Nuvi's Favorites and Recent are automatically saved in Smartphone Link app (and refreshed every time you reconnect), so you can navigate to them using Maps app, when your Nuvi is not available!

After you connect your Nuvi to Smartphone Link and start driving a route, your Destination is saved on the phone too.
You can park your car, take the the nuvi out of its mount before you turn off the engine and your Parking Location is saved on the phone too.
You can leave your Nuvi in the car and continue navigating to your original Destination using your phone with Maps app
You can also navigate back to your car using your phone again.
Even if you don't drive a route but your Nuvi and phone are connected and you take the the nuvi out of its mount before you turn off the engine, your Parking Location is again saved on the phone, so you can navigate back to your car.