Sparkss- The netting, in its natural state, is a tight diamond pattern. You need to stretch it at an angle to get it to a sqare pattern. The net, as new, is pretty stiff and resilient so it can be a bit tough to do with a big piece and only two hands. After I did my first one I happened to read the instructions that came with the netting. It said to soak it in water with laundry detergent to soften the net. I ended up doing it to the whole net. It makes the net softer and much more pliable. The relaxed position of the mesh is now more square so it doesn't need to be stretched at a different angle. Not sure how easy this is to follow without seeing it. I have no idea why it works but it does. These nets are for throwing so you want them to expand to full size in the air. If you don't soak it the mesh would stay tight and not expand.
DarkXerox- screen framing has a channel on one side. Screen is stretched over the frame so it overlaps the frame. You then stuff some spline material (like a piece of rubber rope) into the channel. It pulls the screening into the channel. You then cut off the excess screening. You can see this a bit in picture number 2. It is really easy to do and once you see it, you'll agree. You just need to buy some frame material (usually 6 or 8 foot lengths), 4 corner inserts and a spline tool. The spline tool is a little wheel that pushes the roping into the channel. They only cost a few dollars. You could push it in with a screwdriver but the tool is worth the $3. The framing is cheap as is the spline material. The only expensive part is the netting because you can't buy small pieces. I'll have plenty left over for others when I am done. Your frame could probably be built in 20-30 minutes. Mine took a while because I primed and painted it. I actually painted the inserts with plastic paint as well-which was probably a bit anal.