Ricco, sorry but there really is no shortcut here. You will have to just learn how to play the piano. I started learning to play when I was four years old, and spent the next fourteen years studying the instrument.
Sure, I studied it to grade 8 standard which isn't something you probably need or want to do, but it gives you some idea how long it can take to learn an instrument.
Others' advice on this thread is good: get some lessons to learn the basics (i.e. what note is where on the piano, what key and time signatures are etc), learn to read music, then you will be able to learn the song yourself.
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moto