If the broken key(s) are white, remove the set of white keys with the broken piece.

If the broken key(s) are black, remove two sets of seven white keys. This will reveal the set of black keys, which are twice the length of the white sets.

The key sets can be troublesome to remove. To remove without further damage, make sure to lift up on the top part as shown and push the bottom part of the keys towards the bottom of the keyboard to unhook them individually.