There should be a video on Nancy's Notions or Sewing with Nancy showing it being used for quilting, plus here is one for prize winning quilts.

https://www.youtube.com/watch?v=d_5Xpl53HKc

I use one each time I press seams. I have about worn mine out. The handle is getting wobbly. It's an old model with handle. It's easier to clap with a handle.

My dad made mine. Easy to do if you know anyone who works with wood. Because of the shape and because I use it while ironing, I keep trying to sit mine on the end just like the iron.lol I use mine all the time. Some seams just stay open better with it.

I've used a clapper and seam roll lots of times but not for quilting. The clapper will help make your seam flatter. That's what it's for.... getting seams flatter for wool suits.... because wool is so thick. And the seam roll is for putting inside a sleeve that you've made to press the seam open. Sleeves are so skinny and the roll will fit inside, giving you a place to press open where the seam edges won't show through to the front side.

I guess I don't see the need for these tools on quilts. And, I've made my own lots of times. For a seam roll, use a magazine, roll it up tightly and cover it with denim or other strong weaved fabric. I usually fold the edge of the fabric under and stick pins in to hold things tight. I put rubber bands or string at the ends. Clappers are just pieces of wood with rounded ends and curved edges. Factory made ones are dented on the sides so you can hold on easier but that's not necessary. We had to make our own when I was in college.... tailoring classes.