I tried to upload a picture of the instructions, but it's too close to the end of the auction - so here's what they say...
1) Attach photo to card stock 2) Choose which border width you would like and find which tool lists that width 3) Place the tool on top of the photo so the measurement you wish to cut is printed face up. Align the tool with the photo so the corresponding inner edge of the tool catches on the edge of your photo 4) Using your hobby blade, cut the card stock along the outer edge of the Perfect Layers tool. 5) Rotate your photo 90 degrees, and repeat steps 3 and 4 until all sides of the photo are trimmed to the desired width.