Rotary cutting saves lots of time. Right-handers, you want to begin with the selvage edge at the top away from you. Your fabric is folded in half, so both your selvages are lined up at the top. Then fold your fabric in half one more time, matching your folded edge with those raw selvage edges. We're only going to pay attention to the lines on the ruler for the single ruler method, not the lines on the mat. So I'm going to align my ruler using one of the horizontal lines evenly with the bottom edge that's folded here. When I put my hand on the acrylic ruler I don't hold it flat because I don't have that control. The ruler could slide around. Rather I want to align one of those horizontal lines and put my hand up on my fingertips and that's where I'm going to apply the pressure. Now for some quilters they like to use their little fingers to stabilize this outside edge so they'll take their little finger and push it just off the edge. You want to avoid having your hands anywhere near this edge because that's where the rotary cutter is going to run along. So I use the straight line at the bottom to align my ruler and get it squared up. I've got my fingertips up. And then I'll retract the blade. You always want to make sure that you use whatever that cover mechanism is for your blade when you're not using it. So, I'll retract the blade and square up the edge by pressing down on my fingertips on the ruler, and rolling the rotary cutter away. And straight up that edge. I trimmed off that piece and now this edges is square. Now I can move around to the other side of the table to begin cutting my strips. If you're unable to do that you want to just move the mat instead of moving the fabric, because once you have it squared up you want that edge to stay straight. You're ready to again align the desired width of your strip to cut on that straight edge that you just cut. Put your hand up on your fingertips again on the acrylic ruler. Use your little finger to stabilize it. And you're ready to start making cuts. And again, you're using the lines on the ruler, not the ones on the mat. If these get in the way of your cutting, you can simply turn your mat over and use the back side. But you're ready to roll.