Recording, CD/MP3, and headphones for the Line 6 Spider III 15 guitar amp?

This may sound noobishly lame, but I have a Spider III 15 and have no idea how to use the two Ins/Outs things. I%26#039;ve read the manual but I%26#039;m still confused. How do I connect my MP3/CD player? What type of headphones amd I supposed to use (I use my regular CD/MP3 headphones and uh, it didn%26#039;t work), and how do I record? Yeah, sorry if I%26#039;m a total noob but anything would help.