The ocean plait knot is best formed on a flat surface, at least until you have run two sets of lines through the braid.
Begin by making the first loop in your cord, thread or rope, approximately ten inches from the end of the rope if you are making a dollhouse miniature 1:12 scale knot, ten feet or so from the end if you are making a full scale rug. You will need a short end which is approximately three to four times the length of the knot you wish to make.
You want the main amount of thread or rope to be on your left, leading to the loop, with the short end of the cord or rope crossing above the piece of rope that leads to the main length.
For a 1:12 scale rug you will want the first loop approximately one inch across, but that can be adjusted later if you find it easier to start with larger loops.