How to authorized my laptop's itunes content from the account menu?

How to authorized my laptop's itunes content from the account menu? I'm not able to listen any of my previous songs in iTunes on my new laptop. All my songs have a blue/white cloud with an arrow pointing down, I click each one and a warning reads I have to authorize my computer to listen to them! itunes give me no option to authorize my computer with my account. Also, iTunes doesn't not allow me to add more devices either? Please help. Thanks!