This next step is where we are going to seal the oil pastels into the ATC blank. Using the matte medium and that finger of yours again, rub the matte medium all around the blank ATC. You will see how it starts to liquefy the oil pastels and how the colors will start to blend.
On the last three in the bottom row, I used gesso instead of the matte medium. Using the gesso will lighten any heavy colors you used and give it more of a pastel or softer look.
When you use the gesso just apply a little dab on your finger and start rubbing and blending it into the ATC.