Linda's recipe is wonderful for electronic cutters. If you are using a regular green mat made for paper, you have to remove all of the sticky adhesive first. Then brush on a thin coat of shortening. Do not use butter - use 100% vegetable shortening (butter contains water and milk solids that will change the consistency of your gumpaste). Roll your gumpaste very thin and smooth it onto the greased mat and allow it to air dry for a bit - how long depends on several factors including the freshness of your paste and the relative humidity of your workspace. It should feel smooth with no stickiness at all. You can use your rolling pin to be sure there are no air bubbles under the paste - the blade will catch in air pockets and pull the paste up. I also trim any paste from the margins of the mat and use a paper towel to wipe away any shortening from that little edge where the rollers make contact with the mat.