I'm new at this, so bear with me if I do or ask something stupid. I have a 4th gen 20 gig ipod. I just recently added several thousand songs onto itunes. It is about 37 gigs with more on the way. I have set up a new playlist with just the songs I want on the ipod. , about 17 gigs worth. How do I go about clearing what was on the ipod and adding the playlist?