Sounds in Free pascal. How do they work?

I've been trying for some time to learn how does sound work and how can i implement it to pascal. No succes. I started using 8 bit sound (i believe that they're 8 bit) and tried to copy some songs (like Mario song). I have some questions. 1. How can i use programs to play a song (a real song) 2. Is there any site that gives 8 bit songs but in code (frequency and duration) And one unrelated question.... is there any way to copy a code from a browser to free pascal....? I really new to free pascal.