Like the snail tank? See it a little closer here!
Here are your instructions:
First, you need to cut your pieces, so the chevron lines up. I like using a 3/8-inch seam allowance, so I cut 3/8-inch from where I want my seam to be (the points of the chevron). Line your cutting edge up so it's 3/8-inch from the points all the way down. Cut. Then do the same on the other side. You'll see I also cut the top of my pieces right at the points.
Cut it whatever length you desire. I cut mine 12 inches. Cut each piece the exact same way.
Once you have all your pieces cut, decide which order you want them in.
Line the edges up carefully. Use lots of pins. Then sew together, using that 3/8" seam allowance. Your stitch will hit on the points.
So when you flip it open, it'll look like this. Yay! Finish the edge with a zig-zag stitch. Then continue sewing them all together till you have a big loop. Hem the whole thing.
Cut your bottom skirt layer the same width of your finished top skirt. I used Riley Blake's large chevron which measures 4 inches from peak to peak, so each of my pieces were 8 inches. 8 inches times 8 pieces equals 64. Then I add 3/4" for my seam allowance (or 3/4" on both pieces if you need to cut two. Since I used an old sheet, I had plenty of fabric). For the skirt length, I cut mine 14 inches (2 longer than the chevron top skirt). Sew short ends together. Hem.
Pin your underskirt WRONG SIDE to RIGHT SIDE of your chevron skirt. Since my white layer is so thin, you can see how the right side can be seen through. Sew the top of skirts together.
When you open it up, you'll see the seam from the underskirt, like this.
Press over, so both right sides are showing.
Stitch a casing that's just slightly larger than 3/4". Leave an opening through which to thread the elastic. Cut 3/4-inch elastic to desired waist size, thread through (you'll just thread it in between the two skirts). Close your casing. Done!