Explaination:
Put a dot where all 4 lines meet (the + in the center). Go down one cube from there, then go right two (put a dot at the place you stop on). Now, go back to the center of the graph. Go up one, and then left two (make another dot here at the place yo ended on). Then, make a straight line that touches the two points nicely, and going straight through the center. Put arrows at each end of the line. I hope this helped!