I've actually made two of them now, with two more in the plans. The one pictured above is located in 100% shade, thus it will be used for storage and a work table. The ends will be left open.
I put an overhead ridge pole in for stability, and used some scrap pieces of pipe for bracing the side walls.
I used long screws to secure the pieces to each other, and used the old garden hose pieces to attach the poly sheeting to the frame. Putting on the plastic sheeting was by far the most difficult part of the job.
The plastic hoops were attached to the inside of the ground framing. This means that they push against the wood so that they won't pull away, like they might if attached to the outside of the framing wood.
I purposely laid the 2x4s down flat because when they are upright, I discovered that I tend to trip over them.
Though I forget to take a picture, I secured each of the four corners with a t-post pounded into the ground, with the pipe hoops and 2x4 framing wired to each t-post. Hopefully this will be strong enough to keep the wind from lifting the greenhouse, causing it to blow away. Today we got some gusty Kona winds, giving the greenhouses a test. So far things look ok.
The second greenhouse is in a sunny location. This one will be used for slicing tomatoes. I plan to screen both of the ends of the greenhouse to keep fruit flies out. I'm not sure exactly how I'll do that, so I'll have to let you know when that happens.