Complex sentence: The ground floor in Merchants Street was designed so as to house eight shops, four on each side of the main doorway, and eight square windows on the top floor, one above each shop.
Split into simpler sentences: The ground floor in Merchants Street was designed so as to house eight shops, four on each side of the main doorway. These rooms above the shops have a window each, forming eight square windows on the façade, one above each shop.