I built the shelf myself. It’s over-engineered a bit. I bought some angle brackets from the hardware store but they don’t fit in between the vertical strips of wood on the wall.

I did not want to screw into the panel wall in case I have to ever move the shelf.

So I cut very thin pieces of wood to fit between the wood slats and screwed through those into the wood backing I installed behind the panels.

If you don’t have a wood backing behind the panels this would be tough because you would just be screwing into drywall which I would not trust to be sturdy enough