Iphone...please help?

So i just got an iphone and i want to put my songs on my itunes on it but i want to make sure i am doing it right because i dont want to accidently delete my songs or something. As i was following the directions a screen poped up and it says: this computer has previously synced with another device and it gives me 2 options which one do i choose....1. Set up as new iphone. or 2. restore from the backup of ipod touch.