They certainly would have made things easier. But, you have what you have. Finding grid panels was the first one the list. The internet can be a wonderful time saver. Within five minutes, suitable panels were found and ordered. One down.
Next was how to secure them. As I said, supplies are at a premium, so not everything is always available. But, after many forays to hardware stores, and a lot of back and forth between Wolf and myself (mostly me saying “no, I don’t want it to look like that”), we came to a suitable solution to the beams. Wolf took two brackets used for shelves, put a strip of wood in between to strengthen it, and fastened them together, making one long beam. Adding another bracket on both ends ensures that they don’t decide to shift and come tumbling down (with framed photographs!).

Like he said, they aren’t the prettiest, but they work.
Next up was how to hang the grids onto the bracket. He suggested hooks, but what we found was not going to be used. So, when we located white chain, we decided that that was going to be our only solution. So, he spent some time cutting and forming hooks on each piece.
Then he decided it was time to try it all out to see if the brackets fit the tent.