Help with animal crossing wild world ds?

I bought a ds a while ago and Iv just got ACWW today so im still learning how to play. Im a bit unsure about the wifi thing. So if i get a ds wifi usb cable I can connect my ds and animal crossing game to internet? Does that mean that it will then find friends automatically and allow me to open my gates and have my own friend code and visit othe towns on my ds? please help, im confused.