I left my main laptop at KL and I had no idea how to add new songs to my iPod touch. With another laptop I have and compatible iTunes installed as well as some google searches, I got the idea like this to solve the problem.
1. Plug in iPod to the computer to sync to
2. On the summary page near the bottm, check the box that says “Manually Manage Music and Videos”
3. On the left pane, click the drop down icon just beside the iPod’s name and select music
4. Drag and drop the songs you want to sync to the main pane and voila
Additionally, if the iTunes asks to authorize the computer, on the top bar, click Store, then Authorize computer. Type in your username and password.