How Do You Download Stuff From Garmin Website Onto Gps?

Okay, so you can go to www.garmin.com/vehicles and download different cars to show on the GPS. So I got on to download it for my parents but it says you have to attach the GPS to the computer… how do you do that? Do you need a certain cord?
Thanks so much!!
p.s. I don’t know if this matters but we have the nuvi 260