The other answer someone posted to this question is incorrect.
The correct way to solve this would be:
-12x - 3y = 36
3y = 12x + 36
y = 4x + 12
now that the equation is in y=mx+b form, we can identify the slope and the y-intercept. (remember, (m=slope, and b=y-int)
slope: 4
y - intercept: (0,12)
From here, we turn slope into rise/run which is
4/1
This means that the slope rises up 4 units, and runs right 1 unit.
So when you graph it, you would start off by graphing (0,12).
Once you've done that you count up 4 units, then count 1 unit right from there. The point which you end up with would be your second coordinate. You can create your line with 2 coordinates.