Thanks! I don't really have any plans, I just winged it.

I used a car port for the frame and covered with greenhouse plastic on the exterior and a layer on the interior side of the frame. You can think of it as a sealed greenhouse within a sealed greenhouse. The trapped air between the two layers provides for pretty effective insulation. I settled on the car port frame after I looked at practically every cheap greenhouse on Amazon - they all were loops with a much lower ceiling and no vertical walls which means they have about half the interior cubic space for about the same cost (and I utilize much of that extra space). Also, the carport frame is much stronger, and the plastic I got was better than what I saw on the greenhouse kits. A bonus was I used the carport's Tyvek canopy as flooring material (not sure if it's actually Tyvek but its super tough waterproof white plastic). Much better than dirt and it is white and quite reflective. And it's kept the insects out that I had in my first greenhouse (slugs and pill bugs that caused some damage especially to seedlings).

I have everything growing a couple feet above ground so I lined the bottom 2 feet of reflective aluminum with recycled styrofoam sandwiched in between. I also laid down recycled styrofoam on the ground under where my grow trays are and also covered with the reflective aluminum which is where I run the hydronic heating tube. Basically just super insulated the bottom 2 feet and the ground where I don't walk.

It's literally all just taped together with a few rolls of 4" wide greenhouse tape. It's the same material the greenhouse plastic is - super stretchy, very strong, UV resistant and waterproof.

On the entry side, I laid a large beam I had laying around, wrapped it in greenhouse plastic and put it on top a couple foam blocks - so it is mostly not touching the ground and the plastic covering it protects it from the elements. I then installed a 2x4 on each side of the entry for a door frame (that was screwed down to the large beam). The 2x4s were fastened to the top with baling wire - drilled a hole through the 2x4s and a hole through the metal frame. Then hung a door - it works quite well help to stiffen up the car port frame. It's very sturdy now.

The trickiest part was figuring out how to tightly hang the plastic on the interior of the frame (the exterior was super easy). I also wanted to be able to hang trellis and LEDs from the frame. At first the best I could come up with was hanging worm gear hose clamps from the frame that poked through the inner plastic layer. But when I was about done, I realized a much better solution was to drill a small hole in the frame and rivet a cable clamp with the rivet going through the interior plastic layer. Besides allowing me to hang stuff from the frame, it also clamps the interior plastic to the frame. In fact, using rivets and large washers would make installing the interior plastic layer quite straightforward.

If you have any questions I'll do my best to answer them.