How to sync apps from iphone to computer?

I finally bought an iPhone 4S, yay!!! I bought a few apps then every time when I try to sync apps to my Mac, iTunes pops up saying it wants to delete my apps.

It took me a while but I finally figured out how to sync my apps to my Mac:

In iTunes => under Devices => right click on my iPhone and click on “Transfer Purchases from”.

iTunes would start copying the apps to my Mac.

Once done, I can then tick on “Sync Apps” without a problem.