Pick a value for x. Substitute that value into the function and then calculate the value of the function. Create an ordered pair consisting of the value you chose for x and the resulting value of the function you calculated. Plot the point represented by the ordered pair.
Repeat as often as you like until you get a sense of the shape of the curve.
Draw a smooth curve through your plotted points. Note that if x = 0 then f(x) = 0 and that this is the vertex of your parabola. Also, your parabola is symmetrical to the y-axis.
John
My calculator said it, I believe it, that settles it