Make sure you have the actual iTunes program downloaded. There is a bar on the left called "Source", you should see a number of buttons like:
Below this, if your iPod is connected to your computer via USB(Make sure its plugged in, once I forgot to do that and for about an hour I couldn't work out what was wrong) you should see a picture of an iPod and its name.
If you have got this far, drag the music from the library, or anywhere on your hard drive onto the icon. It sometimes needs converting to a different type if its from a cd.