Welcome to our forums! As Sierra Dragon noted in the thread you originally posted in, this question is outside the scope of that original thread. I dithered quite a while trying to decide where to direct you, then decided that your question is really related to "new MBP" more than "sync iPhone."
The simple answer to your question assumes that you had a MacBook or other Mac that you're replacing with the new MacBook Pro. In that case, you use the Migration Assistant to "move in" to your new Mac. This should not only put all your old files on the new machine, but also make iTunes on the new machine sync with your old iPhone just fine.
If you are moving to the MBP from some other kind of computer, the migration is mor complicated. You don't provide enough information to guide you in that case. I hope you find this useful, and again, welcome to our forums!