So I found this for one of my challenges:

http://virtualpiano.net/

Click that and click menu above the keys. Then click key assist and it should look like this

piano.png

Then go to the music sheets section

http://virtualpiano.net/tag/easy/

And they'll show you how to play some song

The letters written under are the keys on your keyboard to press. So Mary Had A Little lamb is

apopaaa
ppp add
apopaaa
appapo

So just type that and you'll play Mary Had A Little Lamb

TA DA

I am having so much fun with this