Practice cutting paper with the dies until you get comfortable using it. This way you won't waste your fabric. Paper will not hurt the blades at all.
Cut the paper to fit the die, then put the paper on the die, then the plastic mat. Then turn the handle while pushing the die to get it started in the roller. That's all. When you get comfortable then you can cut fabric just to fit on the die shape with about 1/4" over the blade lines.
