Old Iphone, Different Itunes. How do I backup?

Here's my situation:

I have an iphone that I have always backed up on my desktop at home. I have now moved countries, leaving my desktop. I have my laptop with itunes, however I have never backed up my device on my laptop. My question for you guys is how can I transfer all of my information from my iphone to itunes securely and safely so that I can back up my iphone on my laptop and FINALLY start to add new songs to my iphone?

Thanks for any help you might have!