Step 8: Building up!
Grab the tail of the braid that you pinned into the base, and bring it up diagonally to form the bottom row of the basket. Push your needle down through the base as shown in the first picture, and then bring it over the braid and back down through the base to secure the bottom row. Do this every 1-2 inches, keeping the thread diagonal and tight and the braids upright and straight, until you're left with 3-4 inches of thread.
Then, anchor the two layers of braids together as shown in pictures 8-11, and knot on the inside of the basket as shown in the last picture.
You'll keep repeating this process until you get close to the end of the braid, or until you reach a size you like.