How to transfer music from iphone to new mac?

I;ve recently purchased a new Macbook Air after my old computer broke and I was wondering how I can transfer everything I have on my iPhone 5 to this new mac? Every time I connect my iPhone to it it wants to replace everything on it with stuff thats on my Macbook but there isn't anything on my Mac? I have the lasted version of OSX installed and have iOS7 on my iPhone, any help would be appreciated, thanks

See the links below.

Apple had this wonderful plan that people would use their computers to download songs and movies, and THEN sync all that to the iPhone, iPad, and iPod Touch. It got all twisted backwards, and now people use their hand-held devices to buy or steal stuff online. C'est la vie.