On second look, it's a rather elementary lesson, with just chords and songs listed. No real instruction. Some of the song titles have ---titles that I don't really approve--- so I'm guessing that I wouldn't approve of the songs either, but I'm still going to keep the link here.
You can use this as you wish. There are many, many MORE songs that you can learn with just four chords. 220 just scratches the surface. And of course, if you have five, six, etc chords under your belt, then the sky's the limit.
Refer to my tools on here entitled "Plus One--Minus One" which shows you how to take five basic chords, and by adding or subtracting just one note, you can expand your chord repertoire to nineteen (19) chords.