@BT - here is a good tutorial on making an asym tarp from a single width of WP nylon or Polyester.
A 10x10 tarp is just 2 10 ft strips of material sewn together to make 10x10. No blueprints needed. Seam it and add tieouts at corners and where you think you need them along the sides and ridgeline. Plenty of advice here in the DIY thread. Keep the edges straight for your first attenpt. You can try cat cuts later.