Do you use anything to make the chalk stick (i.e. versamark) or do you just layer it straight to the paper?
No, after stamping the image with ink onto card stock, I just apply the dry chalks with assorted flat brushes. After I'm satisfied and have completed the image, I set the chalks with matte sealer.
ETA: Latisha asked about matte sealer. If you check this post: Always and Forever
you will see a supply picture, the matte sealer that I use is made by Krylon. It merely sets the chalk so it won't smear or rub off.