How do I build an inexpensive corner-fitting headboard?

Maybe these will be helpful!

https://www.bhg.com/rooms/bedroom/headboard/cheap-chic-headboard-projects/

https://www.thespruce.com/dreamy-and-totally-doable-diy-headboards-3017296

This doesn't have directions, but it shouldn't be too hard to copy https://sognidarte.com/img/

You can put up a simple canopy, maybe with lights, or folding panels, even a dresser, or table or low Triangle shaped shelf for a lamp, books... (in place of side table)

They could easily be made into a corner, especially the folding louvre screen doors, or other type of folding screen doors. Is your bed centered in the corner or one side up against the wall? Do you want something to lean back on, or just a pretty backdrop for the corner? You can DIY a regular headboard,but the corner will still be empty behind the headboard, if your bed is centered there. I did mention making a triangle shaped shelf, so I went back to Pintrest and found these. And the louvre screens.

Hi Nonae, hope this helps you out.

https://www.realhomes.com/advice/diy-headboards

several ideas here:

https://www.pinterest.com/pin/50243352080031283/

It is easy to make simple padded and upholstered headboard pieces. get soft thick foam and a fabric you like. I used inexpensive flat bed sheets but when I want to change I might use pretty fabric shower curtains. I went to HOME DEPOT with my measurements for height and width of 2 pieces of less expensive pieces of plywood. The associate was great and cut to my specs, because that was her job. I took my wood home and sprayed foam glue on it and applied foam that was cut 1 inch larger on top and both sides. I let them sit over night. Next day I stapled fabric folded over once and used a staple gun to attach the fabric across the top across the back. Next I stapled the fabric down both sides across the back. The bottom which should be at bed frame level will not be seen and does not need to be stapled unless you chose to wrap it to the bottom of the wood and staple on the back side. Since this projects uses 2 separate pieces of plywood I placed them where I wanted them along the walls and pushed the bed(made up) against both upholstered pieces to make sure they fit as I wanted. When it was just right I used thick double sided silicone tape I placed on the back of the plywood to keep everything in place. I placed a small ish low dresser by my bed that was able to hold my cpap, a lamp, and all the other stuff I need by bedside. Whole expense for this project was well under $100.00 dollars. If you do not have a low dresser of your own check thrift shops. It works much better and is far more stable than trying to attach a board shelf to your upholstered head board and side upholstered board. I made my sideboard full length because the wall was always cold. I have moved since making the boards and never left holes in the wall behind me. The new bedroom now has my beautiful fancy upholstered head and side boards to show a beautiful custom made head/side board that looks to beautiful to be a DYI project. If I had found a furniture work shop these upholstered bed pieces would have cost me over $1,000.00! I have a friend with a custom upholstery shop and she gave me that price estimate. That is why I made my own.

Ok! You know what you want to achieve, so draw it on a piece of paper. (pref to scale. Then take measurements of materials required and Go for it!