First of all, congratulations on getting your first iPhone! Technology's latest innovations have been nothing short of amazing and iPhones are no exception. You may be a bit intimidated as a first time iPhone user, but soon using your new iPhone will soon become as natural as breathing.
What you hold in your hands is essentially a handheld computer with cellphone capabilities. You'll be amazed to see just how much your iPhone can do. On your main screen you'll find lots of built in applications such as a calendar, music player, or even an application (or "app") that tells you the weather. While your phone will be fully loaded with useful apps, there are thousands more to download and use as well. The App Store application on your phone connects you these apps that can be downloaded for free or purchased for your own personal usage. The great thing about these apps is that if you buy them, you only buy them once. If you ever accidentally delete an app, you can easily download it again at no additional cost.
iTunes Store Accounts
To download applications, music, and videos onto your phone, you'll first need an iTunes Store account. Don't worry, these are free to set up and can be done either from your phone or from your computer at appleid.apple.com. If you already have an Apple ID, you can use that to sign in on your phone to beginning downloading. While it may seem inconvenient to need an account, it ensures that your download history is stored, making it easier to retrieve any download you may have lost from your phone.
iTunes and Syncing
Even though your phone is much like a computer, it's still very important to have a computer to back up any and all information you store on your phone. With the proper care iPhones don't break easily, but it always counts to back things up. iTunes is the program specifically made for iPhones to sync with computers, and can be installed on both Windows and Apple computers. iTunes allows you to transfer informatino from your phone onto your computer and vice versa.
Just like a computer, your iPhone should be turned off from time to time. Leaving the phone on for too long can cause abnormal behavior and make normal usage a slow and painful experience. The best way to remember this is to think of a person who's gone without sleep for too long. If pushed too hard without a moment to rest, the person will act erratically and even fall asleep at the most inopportune time. The same thing can happen to your iPhone, so turn it off at least once a week if you can remember.
Your iPhone battery has excellent battery life, but the harder you push it, the more quickly your battery will deplete. Unlike older phones, letting the battery die repeated isn't the best idea. When your battery is low, plug it in to its charger so it can be recharged. Don't worry if your phone dies before you can plug it into a charger; your phone won't break if it occasionally dies. Continually letting the battery deplete completely can have a long term effect on the battery life though, so be careful!
Basic Information About Your iPhone
On the left side of your iPhone about the volume switch is the ringer switch. When flipped, you'll notice a red dot that means your phone is in silent mode. This is a handy feature that allows you to turn your ringer volume off without having to go to the sound settings on your phone. At the bottom where your phone charger plugs in are what looks like two speakers. If you play music, you'll notice that sound only comes out of one side. This is because the other "speaker" is actually a microphone.
The speaker option is very good on an iPhone, which makes speaking in the car very easy. In addition, every set of headphones that comes with an iPhone has a built in microphone, so it's a seamless transition from listening to music to talking on the phone.
All of this may seem like a lot for a first time iPhone user to absorb at once, but like with all things, the more you do it, the easier it becomes. Remember, there's always lots of resources online to help you with anything you're unsure of and AppleCare representatives are both friendly and ready to help you at any time. Enjoy your brand new iPhone and most importantly, have fun!