These are instructions for the Astropixel RLD Mount from LayerPrinter Etsy Shop.
Place the Astropixels board on the back of the mount, the wire header goes over the square cutout. Do not over tighten the screws. They should be barely touching the LCD board to prevent damage.
Slide the mount over the screw posts of the dome and ensure its seated all the way down. Use the original screws to secure it into place.
Thats it, follow the Astropixel Instructions for connecting the wires.