I bought a second hand keyboard and a book on how to play. After practicing for two weeks I got the hang of finger placement, chords and a rudimentary understanding of sheet music. It is not hard, just frustrating the during the first week.
Your question isn't keyboarding, but piano, which (my brother was a concert pianist) needs a proper piano and instruction from a qualified teacher. Also you need patience and the willing to become a pianist, and not just a piano player. There is a difference.
You see gimmicks on the web about a video regarding the pianist cheat book, which has the basic chords of a song, but you need to know the basics first and more before you can use it. It looks easy...
Look in the paper for a piano teacher, unless you just want to tinker on the Casio then get a book at the music store. It's the best minimum outlay, and then you can determine if you want to undertake something more serious.

p.s. Oh and don't let anyone, especially the teacher discourage you. If you want to learn to play, ignore any criticism. It is odd but they love to try and tear you down. Some have an elitist attitude, probably due to the commitment they have to make in order to teach you.
