So to get the etched lines perfectly square and also rotated use a carpenter square on the bottom edge of the aluminum. The hypotenuse of the tool is at 45 degrees. Lay your long level on that edge and try to line up the top the level to one of the corners of the aluminum.



Once the level is in place put pressure on it to keep it still as you roll the screen repair tool down one side. Put a moderate amount of pressure, but don’t make it a workout. You will notice two sides of the screen roller. I used the double edge (or concave) roller. I feel it gave me more control on the runs.



Once you rolled your first line, move the level over and use the first line as a guide for the second and roll your next line. DO NOT slide the level across the face of the sheet. You will scratch the surface and not be happy. Lift up the level and replace it in the next position.



Continue these steps until you have the entire sheet lined out in the same direction.