There should be an aluminum tape sticker on the inside flange of each window that identifies the manufacturer and model/part number. I'd guess they are Kinro windows manufactured by Lippert Industries. Their website is:
http://lci1.com/
As for the installation instructions, Springdale RV windows are a common "clamp ring" installation. It's not rocket science, put butyl tape around the outside flange, position it in the center of the frame opening, hold in place while someone goes inside and positions theinterior trim ring in place and screws the two halves together evenly. Don't overtighten, but keep it snug. Let sit for 24 hours and trim the excess butyl tape that has exuded from around the trim ring.
If you go to the LCI website, you can contact Lippert Customer Support from a link found there.