Well hopefully you have a quality cassette player so the CD doesn't sound like crap. That analog background noise that sounds fine off the tape will make your CD sound awful. But if you want to give it a shot all you have to do is plug the output of the tape player into an input on your sound card (marked something like microphone, auxiliary, line, etc.) and record the new input as a .wav file (even windows sound recorder will work if it's all you have) that you can later burn onto a CD. Start a new .wav file for each track. So if it's music stop and start and create new files with each new song off the tape. Then burn each new .wav file as a separate track using a program like Easy CD Creator or something. There are much more elaborate ways, but this is the simplest if you have a sound or video card with audio inputs.