The Dirty Blind
Man®
Most valances are held in place by 4-7 screws. Shorter screws are used to hold the valance in position on the inside wall of the coach. There are normally 3 longer screws that hold the inside top of the valance to the cabinet above.
Most of the time they are star head Phillips screw. Sometimes they are square head Robertson screws. Hopefully they are not slot head screws.
I have seen valances anchored at the bottom with long screws at a 45 (like toe nailing). Others will have the screw hidden behind a button.
Most Day/Night shades will be held in using standard metal tab brackets. These will require a slight flexing of the bracket to release the shade. They can also be released by inserting a slot head screwdriver between the head rail on the shade and the bracket itself, with screwdriver in position all that will be needed is a slight twist of the screwdriver.
Black or brown plastic brackets will have a thicker larger tab and may only require use of your thumb to flex bracket. Remember to be careful, the plastic can break.
Others may have screws through the head rail itself, these will require you to go searching in the folds in the fabric.

Most pleated shades that have a wooden head rail, have long screws through the front of the head rail.
Metal head rails will normally have brackets similar to the Day/Night shade.
I have had customers request fishing line to steel cable. Size does matter. Correct cord weight is essential.
The Day/Night shade itself is a fantastic design, when setup properly the shade performs perfectly.
This is the effect of using the wrong cord. The bushing has worn on side and the cord now runs across the aluminum.
The shade has to much tension on the cords and may wear out the bushings or break, if it is to loose it may slowly drop down by itself.
Day/Night shades require time and patience to set up.
Final adjustment is done at the cord retainer.
This is due to the shade not being squared. Head rail, middle rail and bottom rail must be in correct position during operation.
This is usually caused by a missing end cap.