When you first get your iPhone, you may be confused about how to use some of its basic functions. There are plenty of icons on the screen, but very few buttons on the phone itself. And since the iPhone 3G and 2G don't have a proper manual, something as simple as figuring out how to turn up the volume on the phone can seem like solving a mystery.
Press the center "home" button to activate the iPhone's screen and bring it out of sleep mode. You will see the time displayed against your chosen background and a small gray arrow at the bottom.
Slide the gray arrow on the home screen all the way to the right to unlock the iPhone. You will hear a "click" sound when the phone is unlocked, and you will see all of your icons pop up.
Find the long button on the left side of the phone with the small indentation in the middle. This is the volume toggle. It controls the volume for your music and videos, as well as your ringer volume.
Press the top part of the button. A small volume icon will appear on the screen showing you your current volume in relation to the device's maximum volume. When you are finished adjusting the volume, simply stop pressing the button and the volume icon will disappear automatically.
If you are using earbuds, make sure not to set your volume too loud as it can damage your hearing.