HI there. My name is***** would be my pleasure to assist you with this.
To update your Garmin, you will need to use the data cable that came with your device. After you have connected the Garmin Nuvi to your computer, please click the link below to download and install Garmin Express (a free program)
After the program has been downloaded and installed, you should see the option in the program to update the unit and to install maps.
Please give this a try and let me know the results.