External harddrive

Hi I just wanted to ask two questions if I may.
I have Norton 360 Plantium on my desktop and laptop both HP Pavillions
Question one is can Norton let me safe on an external harddrive and if so how do I do it.
Second question is if I can safe on external harddrive does Nortion do it for example every 30mins or every hour or do I have to physically do it my self pick file and transfer it to external harddrive.
Can you replies be as basic and easy to understand as I am not a computer person.
Also thank you all in advance