Figure "A"
Cut floor plywood either 4x6 or 4x7 and frame 2x2's around outside edges. This will be the bottom and sit on the ice. Next determine side of hole you want and cut it out, saving this piece for your lid to cover hole when not spearing. Make sure you leave an inch or so from back end of "A" se you can hinge the lid
Figure "B"
Finish framing in the bottom with 2x2's and around the hole, leaving 1/2 inch support for your hole lid when you are not spearing.

Figure "C"
On the door end of figure A you will need to put a 2x2x48 on the floor and then a 1x2x48 on top of it. The 2x2 will need to be notched so we can put a 1x2 into it to hold the canvas tight. The 1x2 will be the same length as your floor length. Putting the canvas on will be your last step and the 1x2 will snug it up and keep in place. Again, this is what the notch if for.

Figure "D"
This is your back wall by your spear hole. Make it a bit shorter than your flooring is long, so when you fold it down, it won't overlap the end. You can round the top ends of your house using a garbage can or whatever, just so you get them even. Then support them with 1x2's . This will help also prevent warping, etc. we are going to use 1/2 inch galvanized conduit pipe (2 pieces) to prop open the ends and keep house up, so either cut notches or holes on the upper 1x2x44 so they will fit when you erect your house. I used a one inch bit to make a slot for the pole to sit in, instead of a hole. Make this end 3 inches right hand figure "E" because figure "E" will be sitting on and extra 3 inch support in front.

Figure "E"
This is same size as back wall. Support it with the 1x2's just like in figure "D" and notch out for poles. Then cut your door size as desired, frame and hinge on. Frame your door from the inside so when the shuts, it is flush with outside and resting against 1x2 which should provide lip for door.
Use a 48 inch piano hinge to connect both front and back walls to floor.

The galvanized pipes, 2 of them should be same length as house.

Putting on the canvas can be tricky. Lift up both ends of your house, put your 2 pipes in their slots and tie a noose rope around the house to keep it in place as you put up canvas.

Note: When putting on you canvas, fold it in half lengthwise and mark center with pen or chalk. Mark the exact tip middle for both front and back walls so you can match up with center of canvas. Make sure you have purchased length of canvas long enough to overlap each end several inches. Start stapling from center to either side a foot or two and got to other end doing likewise. Stretch good, doing a few staples front and back, so you get it nice and straight. Stop stapling a foot or so form the bottom so you can fold it down. Put on he 1x2 as shown in figure "C" from front to back and tack down form the inside of the house. This will snug up the canvas.

You can make skirts for each corner bottom and glue them on the outside to keep cold and light out.

It a good idea to measure and see how much canvas you need, but 17 or 18 feet should be enough. Any leftover should be saved for small hole you may make in the canvas later. Just glue a patch on.

For hanging decoys, get an extra piece of the conduit 3 feet long. Get a pair of 72 inch leather boot laces, using one to slide all the way through the pipe and tie each end to the pipes supporting the ends. I use key rings that I have slid form one side to the other. You can also slide front or back on the support pipes. This gives you a lot of ways to move your decoys. You should also get some black electrical tape and wind around your pip to keep glare off.
I also put some cheap carpeting on he floor for warmth and noise reduction.

Also on your spear hole lid, lift it up and put an eye screw underneath in the right-hand corner nearest you. Lift the line and rest it against the back wall. Put another eye screw in the wall, attach a piece of cord to it and tie to lid to keep it from falling shut. When done spearing, untie it leaving cord or leather shoestring attached to eye screw on back wall. You should also have one on top of lid so you lift it up when you get into your house.

When you are ready to leave, you pull out the long pipes on each side, lay diagonally across floor and let back wall come down first, then front side, tuck canvas in and you're ready to leave.

On figure "E", I also show a 3" hole for stove pipe, I use a small gas stove and I ventilate it with 3 inch pipe.