How to transfer my iPhone 5 and iTunes to a new laptop?

I have bought a new laptop today and would like to set it up so my iTunes and iPhone 5 are on that not the old one.

Added (1). But i don't want to lose the contents of my iPhone? How do I preserve it?

I forget exactly how to do it but i've done it before when i got my new desktop
You can google it, search for itunes backup
I think it allowed me to backup my whole library and everything to the iphone and when you plug it into the new computer it will download it all back into itunes
I believe you can also do it with a cd but its probably easier with the iphone

Very easy,

Just you need an external storage so you can move the files from the old to new laptop.
(Make sure that iTunes is not running while you're doing this step on both computers)

Go to your Music folder.you'll find iTunes folder, just copy that folder and put it inside an external storage then go to your new computer and replace the iTunes folder under Music directory with the iTunes folder that you've copied from the old computer.

Now, open your itunes, and your library should be appear as it is on your old computer.

same thing you do if you want to format your laptop or restore it to factory settings.