You should connect the OUT sockets on your amp and plug them into the LINE IN socket on your PC (light blue IIRC).
You need to get a 2xRCA (most of the time) to male stereo minijack cable.
I did do that some time ago, but I quit as it's a very tedious process :
- recording is in real time
- there is some editing to be performed if you want to have the songs properly laid out (otherwise you might get anything between one tenth and five songs per track
)