How do I?

I just reseived my Passport and I transfered all my music on to it.  No I want to free up the space now on my cpu and delete those files.  Now to I want to put itunes on the Passport also so nothing it d/l to my cpu and directed to the Passport.

Make sure that you have more than one copy of everything in case a problem develops with the passport, like you drop it. Never trust important data to just one drive no matter who makes internal or external.