Here is the link to the article we decided to use to make our hoop system:
http://www.grit.com/farm-and-garden/pvc-hoop-house-zm0z13jazgou.aspx
They run on a rail so that you can slide the hoops to the end of the bed out of the way or squish it in the middle - that way you can get to various parts of the garden bed but not have to disassemble the hoops. We decided to go with this retractable system instead of individual hoops or hoops that attach to a hinged "lid", due to the size of our beds (4 ft x 12 ft). It does well and I'm pleased. And it will let us put on shade cloth easily for the summer.
We used 10 ft lengths of PVC pipe and to stretch over the 4 ft wide bed, it gave us hoops roughly 4 ft tall - so good size for even things like tomato plants. The tall hoops we made are a little over 6 ft tall - we cut the pipe in half and then used elbows to attach the top pipe - they are more squarish looking and are in 3 pieces as opposed to the short hoops that are just one piece of pipe.
We used washers and small exterior screws and screwed the plastic onto the pvc at the bottom of each hoop except for the end hoops which had screws/washer at the bottom on the side and then up at the top middle and then partway down on each "shoulder" of the end hoops. Not my favorite way to do it but we didn't have any of the special clamps you can get to hold stuff on. The screws and washers work and we haven't had a problem with the plastic being pulled out with the high winds - we used washers that are pretty big, I think they are a little over 1" in diameter but they are the ones that have a small hole in the middle just big enough for the screw. I did end up getting some Snap Clamps to hold the end sheets onto the hoops and they work great. For the ends we basically just hung a sheet of plastic, and then put the top and "shoulder" screws into both the end curtain and then length of plastic. Then I use the Snap Clamps to hold the plastic in place down low on the hoops but I can still take off the clamps to roll up the plastic and tie it up with a piece of rope to get it out of the way. Got the long Snap Clamp pipe tube because it was cheaper, and then just used the chop saw to cut the Snap Clamp pipe into 4 inch long pieces to go onto the hoops. Here's the link for those you can look at:
http://www.greenhousemegastore.com/product/snap-clamps/s
For staking we put a screw into each side of the end hoops about half way up the hoop - that's to keep the rope from slipping. Our beds run from northwest to southeast so the ropes are tied around the end hoop on each side above the screw and then we used tent stakes to anchor into the ground. The tallest structure we made also has rope coming from the top of the end hoops going to the ground since the tall hoop is over 6 ft tall to accommodate the trellises for the peas/beans. It took several different days of winds coming from different directions and seeing how the wind pulled the hoops off the rails, and then we could tell from which direction we needed to add a rope and stake. Just used the same color poly rope that we use to hang poultry feeders/watering buckets - has like a 50-90lb rating on the rope. Basically it's like staking a tent in the wind. Once you see how the wind is blowing your hoops around, you can see right away where to tie a support line at.
Here's a link that has the photos I took of our hoop set up:
http://www.polarisstarfarm.com/adventures/2013/12/01/winter-gardening-begin/