First you have to make sure that you have your contacts, tasks and calendar in iCloud. Do you even use iCloud?
If yes, then you select to set up as new, and when the setup assistant asks you, you login with your iCloud ID and the system will set up everything for you.
Do you have your pictures in iPhoto or Aperture? If yes, then you connect your device to your computer by using the USB cable that you got with your device, and then select to synchronize your pictures with iPhoto. You can even do selective synchronization.
As I wrote before, you have to make sure that everything you need is stored in iCloud and/or your computer.