I'm not sure how to explain to you exactly, but see the numbers marked on the x and y axises? They are how you determine where the points are. The coordinate's format is (x, y), meaning that if the first number is positive, you go to the right (negative goes left) and if the second number is positive, from where you left off from the first digit, you go up (negative goes down). So in this case, since each grid is marked in 2s, you'd go in the middle between the main axis (horizontal) and the 2 and down 6 from there (To where it is marked -6). For the second point, you would go to the right to where it is marked 4 and go up 3 from there. Then, just connect a straight line through the dots (And make sure it continues since its not a line segment) and you've got your graph.
Hope that made sense! :)