The iPad needs a micro-SIM card (the iPad mini needs a nano-SIM) to connect to a cellular provider. Without it, you won't be able to access cellular Internet, only Wi-Fi. This SIM card comes preinstalled, though if you go abroad you can also pick up a SIM from a supported cellular carrier.
If you need to install a SIM, or access your current SIM card, you can remove it by sticking one end of a paper clip into the hole next to the SIM card slot, visible on the left side of the device.
You can set the iPad and iPad mini's Side Switch--located on the right side of the tablet near the top--to lock the screen orientation or to act as a mute switch, depending on your preference.
To set this, go to Settings > General, and then tap Lock Rotation or Mute in the "Use Side Switch to" section. If you choose Lock Rotation, toggle the screen-rotation switch on the side of the iPad to expose the orange dot, and your iPad stays in either landscape or portrait view, regardless of how you're handling it. When the rotation lock is engaged, a small icon showing a lock with an arrow around it appears on the right side of the status bar near the battery icon. If you select Mute in the settings screen, the switch controls the iPad's Silent mode, which mutes alert noises. Be advised that you can still hear the audio from music and videos from the device's speaker when the iPad is in Silent mode.
Volume Up and Volume Down Buttons
Directly below the Side Switch is a rocker button for volume. Press the top of the rocker to increase volume and the bottom rocker to decrease volume. (In the Camera app, the top rocker also functions as a physical camera shutter button.) In the Settings app, you can choose whether these buttons affect only noises from an app, or whether they control systemwide sounds as well.
Transfer your data
Whether this is your first iPad or you've had tablets that came before, chances are you're going to want to load it up with some data. Here are the various ways to do so, depending on whether you're moving from an old iPad or your computer.
If you're upgrading from an older iPad
You're moving on up to the latest and greatest in the iOS world, and to do so, you're leaving your old device behind. But before you send it off on its last voyage, you have to decide if you want to transfer its apps, data, and settings to your new iPad. If you do, you'll need to make a backup (via iTunes or, if your old iPad is running iOS 5 or 6, via iCloud) of your information.