The first one will be the tech, that gets you on the air, mainly VHF/UHF or local frequencies. Also you get a taste of HF or "shortwave", as most people know it, with the tech. General gets you a little more HF bandwidth.. Extra Class gets you the entire HF bandwidth
You'll have to start out as a tech. Go ahead and study for the General while you're at it. There have been those who walk in without a license and walk away with an extra class license.
HF or high frequency lets you talk around the world, depending on equipment, time of day, sunspots, weather etc. I've talked to guys in Switzerland, Australia, and England, all on 100 watts.