First choose what you plan to use to make your stamp. I chose Tim Holtz fragments.
I placed them on my contact covered chipboard so the spacing and layout was slightly larger than the moldable foam I was using.
I heated the moldable foam with my heat gun and immediately placed it on my fragments. I pressed down as hard as I could to get the impression for maybe 10 seconds.
When I lifted it up and turned it over this is the impression I was left with.
Here is the stamped image after inking and pressing on white card stock. I like it. Not perfect however, I can see using it on some ATC's for a background. Maybe next time I will choose elements that are a bit thicker to get a more crisp stamp. And if it doesn't turn out that is the good thing about the moldable rubber. You can heat it again with your heat gun and make a different stamp.