If you want to play 'Twinkle, Twinkle little Star' on the piano you should first start on the note D. You should play the notes going up the scale to find that next work that matches the tone of when you sing it. When you find it, that interval is a fifth. Then, the song goes back down again in steps. Your melody will work in the scale of the notes that you have just played. There are three parts to the whole song that you should learn. You will use all the notes found in the D Major scale. Now, to play the chords that go along with the song will be a G chord. When you come down in the song, you should play the C chord then back down to the D and then the E chord. Remember, your G Chord will be the root chord of the song!