How do I record from my stereo to my toshiba laptop using a audiobox usb?

Since your stereo probably does not have quarter inch outputs you would need to purchase adapters or cables that run from RCA to quarter inch terminations.

However, plugging powered sources (such as mixers, guitars/basses with active pickups, stereos, etc.) in to the AudioBox USB is not recommended.

This is covered in the AudioBox USB manual. Screenshot attached.