If you have iTunes 11 turn on the Sidebar. Go to iTunes>View and click on Show Sidebar. You can also do a Crtl+S to show the sidebar. The sidebar is where Devices appears. and Control+B to show the Menu bar
Then, if necessary:
Thanks so much for the speedy response.
I fear that I haven't explained myself very well.
I have all my music and vids on the iPod Touch (3rd gen.)...but when I plug it into my iMac (Snow Leopard), the music files are not showing in iTunes (11.2). The iPod shows up and when I click on 'on this iPod', I can see my playlists and songs...but the songs are not in iTunes and I can't add new playlists. Sync doesn't seem to be helping.
Have you synced music for this iTunes library before?
To transfer iTunes purchass to computer:
In iTunes 11 use Control+B to show the Menu bar then go to iTunes>File>Devices>Transfer Purchases. make sure the computer is authorized for the account.