Nail each end of the redwood stakes to make a frame, and then toe-nail in each corner to provide stability. Measure on the inside of the frame 7" in each direction, and nail a 1/2" brad at each of those point, and leave about 1/8" of the brad showing. If the frame is laid flat on the gound, all the brads should be facing upwards in the same direction.
Take the nylon cord, and tie around the starting corner brad, then loop the cord around the brad on the opposite site of the transect, and move to the next brad, loop around it, and then travel across to the opposite brad. Continue back and forth, and tie off at the last brad. Then repeat to form a net-like structure, with 20 - 7" x 7" squares.
The way the transect works is that each
square represents 5% of the whole transect, the the transect is
used to measure canopy cover about one foot off the ground. With
this design, it is easy to measure species cover down to <1%.