(Rise) Using the farthest dot on the left you count how much you rise till you align with the second dot <em>(depending on whether you go up or down determines + or -)</em>
(Run) Once aligned with the second dot count whilst 'running' towards it till you've reached it.<em> (If you go right it's +, if you go left it's -)</em>
Hard to explain, but it's really easy if you look up a tutorial.