You should know that the graph of y = x2 is a parabola.
The negative in front flips it upside down, the -2 moves it 2 to the right, and the +4 moves it up 4. You should have an upside down parabola with a vertex of (2,4). You may want to input other x-values to find other points.
f(1) = -(1 - 2)2 + 4 = -(-1)2 + 4 = -1 + 4 = 3, so (1,3) is a point on your parabola.