This walkthrough really needs a rework. The most important thing which is constantly skipped is your initial reference point. For example from 15 I went and found 15.1 and finished that but you then reach a situation for 16 going into the Lower Ziggurat and we have no clue where the "start" is. Is it down and right towards sanctuary from the end of 15? Is there a different entrance they're using?
The point being for this walkthrough to be legible and helpful all starting information should begin with stating which sanctuary you start at. At least this way people can place a guide, look at the travel option, and choose the appropriate sanctuary that they should have gone through from the previous steps in the walkthrough to begin the next.