Camera Speed Ipo problem

I have a camera following a path. i want the camera to stay still until frame 250, then move it along its path. im very new with ipo curves and was wondering if someone could tell me how to get started? i changed one screen to the ipo editor screen, but there is no speed setting down the side. pllllleeeassse some help me!!! lol

ah, i think ive done it - i used time instead of speed…