How to install a screen

Lay the screen frame on a clean, flat surface. The secret to success is to secure the inside of the frame. This allows you to roll the new screen in tightly without bowing the frame.
Cut the window screening at least 1" larger than the outside of the frame. Measure aluminum screening 1/2" in from the corner and cut at 45° to make tucking in the corners easier.
Start at one corner with the roller angled to the outside and roll the spline down into the groove. With aluminum screening, pre-crease the screen into the groove with a gentle back and forth motion.
At each corner, tuck the spline down into the frame. Use a sharp trimming knife to cut off the excess screening.