This is a reply from Garmin support with instructions:

Thank you for contacting Garmin International.


I would be happy to assist you with this;
Garmin has partnered with Google to allow the transfer of addresses and POIs (Points of Interest)1 from Google Maps to the Garmin device.2
For the transfer you will need:

  • A computer with Internet capabilities
  • A compatible Garmin Product3
  • A data transfer USB cable
  • Garmin Communicator Plugin4

To transfer a point from Google Maps to your Garmin device:

  1. Plug your Garmin unit into the computer via the USB
  2. Search[Only registered and activated users can see links. ] for the location you wish to send to your Garmin device
  3. Click on the more option under the address in the left pane
  4. Click Send
  5. Select GPS under the Send To: menu
  6. Select Garmin under the Brand drop down menu
  7. Change or Enter any wanted information in the Name, Phone Number, or Notes fields
    • Information in the phone number and notes fields may not display on all devices

  8. Click Send
  9. Garmin Communicator Plugin will search for updates to the Communicator as well as your Garmin device
  10. Click USB
  11. Click the Box next to the Garmin device plugged in
  12. Click Send to GPS

The address you searched for will now be available in the Favorites list of your Garmin device.
Notes:
1 - Google does not allow routes to be transferred from Google Maps to the device.
2 - Compatible with the following internet browsers: Internet Explorer, Mozilla FireFox and Safari.
3 - Compatible Products:
Code:
Please Login or Register to see the links
4 - Garmin Communicator Plug-In:
Code:
Please Login or Register to see the links