Everything is custom made. Shelf brackets made at a Sheetmetal shop. They are l-shaped 1/4" steel brackets. The Sheetrock is cut out so that steel brackets can be attached to the studs. Then the cutout is plastered over. The shelves are made in two pieces (top and bottom so the shelf sandwiches the bracket. A nosing is added to the face to hide the seam of the two pieces of shelf coming together. Hope that makes sense

Yes that makes perfect sense to me. Thanks so much! I was hoping it was some sort of U shaped hardware that I could purchase. I'm trying to find something that's ready made, with a back plate to attached to drywalled studs, with protruding prongs that could receive the shelf material.

Use Ikea shelves and their hardware and then if you want to upgrade, have the shelves made out of whatever material you want.

Could you please tell me what the ceiling is? Thanks so much!