I have not replaced any of my Day-Night shades, but I have restrung many of them.
Every shade is different in my rig. The side valences are attached to the wall using angles that are screwed first to the wall then the valences are attached to the angles. The exception is the valences that are up against a cabinet. They are screwed to the cabinet. You should be able to see the screw heads inside the valences.
The top valences are screwed to the bottom of overhead cabinets where there are overhead cabinets, otherwise, IIRC, they used angles, but I am not sure on this. These screws are more difficult to see than the sides.
Class C, 2004/5 Four Winds Dutchman Express 28A, Chevy chassis
2010 Subaru Impreza Sedan
Camped in 45 states, 7 Provinces and 1 Territory