S-Dragon process photos

Hi! thank you for this amazing tutorial! I am working on making one now and I am stuck on the tail tip.. on step 38, where I need to add brick stitch rows. How many rows do I need to add? And how many beads in each?   Also my last row has only 4 beads like step 37, but 38 looks like there is more. The diagram shows the spikes being connected to just one string between 2 beads but I don’t know which string I need to use. I’m sorry for my ignorance 😆 please help