Welcome and congratulations. You wouldn't be here unless you had just gotten your license, so lets get started with some basics. To call your friend, tune to a pre-arranged channel and say "WRGF555, WRNG666.". Friend will respond with "WRGF555, Hi, Jeff" (or whatever your  name is). You two can chat back and forth without using call signs for a maximum of 15 minutes although most users identify their stations much more frequently than that. It is in good taste to pause for a few seconds between your friend's transmission and yours to allow other users to ask to use the frequency. Except in emergencies, you are under no obligation to surrender use  immediately, but being a nice person, you will probably do so as soon as practical. Emergency or urgent traffic ALWAYS has priority over routine trafic.