I got a new I

Question

I got a new I pod nano chromatic and I want to be able to sync it manually so that I can delete music on my computer without deleting it from my I pod. It said in the manual that it has an automatic sync meaning whatever i do to my list it does on my I pod. I can not seem to figure out how to change it to manual sync. the instructions that it gives in the manual are not clear and i do not see those options on the i tunes screen.