First things first, you need a data usb cable for your garmin, a data cable wont be bent or curved where it plugs into the garmin, if its curved or an L shape its p robably a power cable / non data.
If you have a data usb cable, then this is where we start.
First, download and then install Garmin express on your Pc or Mac. You can download it from this page
Once downloaded, open and install the program, and once you have the program on screen.
Connect the garmin itself to your computer via the USB cord and then turn it on. Garmin express should see it, and offer you to update the device. Be prepared, the updates can sometimes take a few hours, and its not a good idea to interrupt the update once its started.
But that will get you updated, if you get stuck or run into any issues, let me know!
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