If you don’t have a hard floor available, just place a similarly hard surface on top of your carpet and work on that. Or, use a raised hard surface that you can easily place your foot on, like a workbench.
The extra inch is for your seam allowance, which gives you some extra space to sew your seam so you don’t end up with a boot liner that’s too small for your foot.
Only cut along the outline, not the fold. You want to keep this intact so that you still end up with a single piece of fabric despite the double layer. Since you’re tracing along the outside of the boot for a liner that goes inside, you don’t need a seam allowance because there’s already extra surface area to your fabric.
Later on, the cuff will be sewn along the top of your leg piece so it can then fold over the top of your boot, so how big of a cuff you want is entirely up to you.
The top of the rectangle is where your toes will be. The bottom is where your heels will be. The half-parabola should start out by curving from the top folded corner (where your middle toes will be) and gradually turning inwards toward the opposite bottom corner. Once you pass the point where your toes will meet your foot, the cut should then nearly straighten out on an almost direct line toward the opposite bottom corner. You should now have three pieces: a larger piece with the fold intact, plus two smaller pieces trimmed off. These two smaller pieces can be discarded.
You should now have two pieces: one big, one small, both with a folded edge. The smaller one can be discarded. When you unfold the larger piece, it should resemble the Starfleet insignia from Star Trek.
Do not pin and sew the ends of the half-parabola together where they meet at your heel. Leave them open for right now. When each one is finished, they should resemble a pair of booties or slippers.
As before, don’t pin and sew the back of the leg together just yet. Just worry about sewing the leg piece to the half-parabola for now.
