Z U L8R basically said it all.

I assume you have a dohc from your pic...
Make the cam gears point up by making the exhaust cam gear's 3 o clock notch on the cam gears teeth line up with the intake's 9 o clock notch. These notches will line up with the bottom of the valve cover as well.

Pull the crank pulley off. Look at the crank sprocket and there should be a line on it. Match the line up with a little triangle arrow on the oil pump. Now throw the belt on without moving anything.