For
Sherry, who asked... The big white areas in my studio are 48" x 96" pieces of 1/2"
Homasote. I painted them white, then attached them to the walls in that room. You can get it at the big box hardware stores. It is relatively lightweight, takes paint well, and is easy to cut.

You can also cover it with fabric, as I did for the bulletin board on this closet door.

It makes an excellent bulletin board, especially since you can cut it any size you want (use a sharp utility knife, score it once using a ruler, then make repeated cuts until you get all the way through.)

Since I originally set up that room as an oil painting studio, I painted the homasote panels white.
If I had originally intended the room to be a quilting studio, I would have covered them in flannel. Since the panels were already up, and I had a piece of flannel and an electric staple gun, I ironed my flannel, turned the ends under, and then stretched and stapled it to one of the homasote panels using 1/4" staples.
Yes, I could have bought more flannel, made it the "right size and then stapled it all around, but I didn't need a gigantic design board, and I wanted to GET IT DONE!
You can see the staples along the edges in this picture.

As for the clips across the top of the panels.... They are simply small picture hooks nailed into the homasote (remember the homasote is 1/2" thick) to which I have hung metal binding clips like
these.

They're handy to hang a quilt up on the wall if all you want to do is photograph it. And after photographing the first quilt, I just left them up there because it was easier.

And I was a bit lazy.