don't have a folder to download iTunes to

Hi, Trying to download iTunes music to my iBook G4. Get the window that says need write permission and that I need to have a folder available. I have given myself read and write permission, but can't work out the folder issue. They say go to iTunes Store > Downloads, but there is no 'Downloads' link to open in iTunes Store. Can someone help get me into the 21st century, and let me know how I can go about setting up a download folder acceptable to iTunes?

Thanks