Here's How

• Step 1: Measure inside recess of windows where flyscreen will be located. This may be internal or external, depending on your window. Measure top to bottom on each side, and side to side at top and bottom of recess that frame is to sit in. Note sizes and subtract 2-3mm from each measurement to allow fitting clearance.
• Step 2: Before measuring framing, cut a 45° mitre at 1 end, using a mitre box and hacksaw. Then measure from long point, with the spline channel on inside of frame.
• 
  Step 3: Using a mitre box, cut other mitre on that piece of framing, then repeat, measuring and cutting, for remaining 3 sides.
• 
  Step 4: Assemble frame on workbench by pushing frame corners into aluminium sections. Once assembled, test-fit frame in window opening before you start fitting mesh. If it’s too tight, it’s easy to fix at this stage by disassembling and cutting equal amounts off pairs of frame members, as necessary.
• Step 5: Lay frame on a flat surface. Roll out screen mesh over frame then, using scissors or a utility knife, cut mesh so it’s about 50mm larger than the frame, all around.
• 
  Step 6: Align mesh so it is parallel with edge of frame. Using your thumbs, carefully push spline into channel along 1 long edge, making sure mesh stays straight. With 1 side in place, use end of spline roller or a large blunt screwdriver to push in corners.
• 
  Step 7: Follow along line with spline roller, to push spline snug into channel. Continue around screen. The last
  2 sides will stretch mesh taut as it’s worked into the channel.
• 
  Step 8: Use a utility knife to trim around outside of spline for a neat finish.
• Step 9: Stand screen in place, then mark positions of turn buttons. There are many ways you can attach screens and the correct system depends on where the screen sits in your window. Screw on buttons or clips, stand frame in place, and turn buttons to secure.