Trying to figure out how to put music on an iPod? No problem. Make sure you've already installed iTunes. Apple's iTunes is easy to use, and can be found here.
Next, you'll need to locate the USB cable that came with the iPod. Plug this into your iPod and your computer.
After a few moments, your computer will recognize your iPod and open iTunes (if it isn't already open). On the left column, you should see an iPod icon with the name of your iPod next to it.
At the top of the left column is "Music." This is your music library and should have all your music in it. If it's empty, check out How to Download MP3 Music.
Transfer the song you want by clicking and dragging the song to the icon of your iPod. Release the mouse button and iTunes will transfer the song.
If you want to transfer multiple songs, hold down Shift while you're clicking to select multiple items. If the songs you want to transfer aren't adjacent to each other, you can use Control-click to select multiple, non-adjacent songs. Hold down the mouse button and drag the lot to the iPod. It will take a few moments for all the songs to be transferred.