This template should fit most standard sized keyboards.
Simply print it out, and cut out each coloured strip and place them along the top of your keyboard in line with the notes in the order shown in fig.1
Be sure to line up the Red Middle C with Middle C on your keyboard.
If you are usure where this is, it is the C note closest to the middle of the keyboard (a white key immediately to the left of a group of two black keys, as shown