You have to rearrange the equation so that it's in slope intercept form, y=mx+b. You have to move 5x and 8 to the other side of the equal sign:
2y=-5x-8
Then divide both sides by 2:
y=-5/2x-4
In y=mx+b, m is slope and b is the y-intercept. So, the slope is -5/2 and the line intersects the y-axis at the point (0,-4).
The easiest way to graph the equation is to graph the y-intercept first. Then, because the slope is -5/2, and slope is rise/run, you go DOWN 5 units and to the right 2 units from (0,-4). You repeat this multiple times. To get the points on the left side of the y-axis, you go UP 5 units and left 2 from (0,-4). Repeat.