i try to sync my ipods music to my new laptop and tells me that it will remove all of my ipod and replace with itunes library(which is blank) pleas help

I just got a new laptop and i have an ipod touch 4th gen, and i want to sync my music, and it told me its gonna delete all the music from my ipod if i proceed and it will replace it with whats in the library, yet nothing is in the library.. I just want to make it quick and easy, put whats on my ipod(music, apps etc.) move it to itunes so its on both my ipod and my itunes library, someone please help me