This gets so confusing to me so sorry if I ask stupid questions..but where and how do I define the method?

where would that go?
i put it here
public Color newColor(Pixel pixel);
public double colorDistance(Color newColor, Color targetColor) {
Pixel [] pixels=_picture.getPixels();
int...

ASSIGNMENT: In section 6.1 of the text, the
authors explain how to compute the distance between two colors. They write,
The Pixel class has an object method colorDistance(Color color)
which...