Someone has given me an old iPod ClickWheel 20Gb classic. I'm totally new to this world of iPods. I'm on a Mac running 10.7.4 and iTunes 10.6.1 (7).

1. I have a huge library, way beyond 20Gb. I used to listen through speakers attached to my Mac. The vast majority of the "songs" are checked for syncing. How do I uncheck them all? Similarly, once I've located the "songs" I want synced, how do I mark them? There doesn't appear to be a command to mark or unmark all.

2. A great many of my songs have an exclamation marks next to them. If memory serves, this icon used mean the item could not be found on the hard drive. Yet all the ones I tried to play today instantly worked. Why the ! mark? How do I get rid of them all?

3. There's a lot of items with gear wheel icons similar to ones in Mail. However when I double click on the icon the rules for the "collection" don't present. Nothing does — either an empty screen opens or one with a static collection of music.

4. Various iTunes menus offer these commands:
• Deauthorize Audible Account
• Authorize this computer
• Deauthorize this computer

What are these commands all about?

5. After iTunes loaded up my iPod with as much music as it could squeeze into 20Gb, I dismounted the iPod. Plug it back in and no devices appear in the lefthand side of iTunes. What made the iPod mount this morning was that I was booting the Mac with the iPod already connected. In future I don't want to be rebooting this Mac every time I want the iPod mounted. Is there a hidden alternative?

Appreciated.

( when your iPod shows up in Devices in iTunes)
1. You can choose which music to sync from the 'Music' tab. Select your iPod in 'Devices'. In the Music tab (your device page will show your options), you have choices to sync entire library, sync selected artists, albums, genres and playlists. You can also choose to fill any empty space with songs (random).
Further down that page, you can check (uncheck) which artists, albums, playlists etc to sync to that device.
Making playlists (and selecting/deselecting) makes for a much faster way to add music and variety.