Window Ring Screws

Hello All! I bought some new RV windows from a private party. Fixed RV tinted windows, 18x24ish
THey did not come with screws. My question: What length screw do I need for the installation of the window ring, with a wall 3/4" thick? Thanks
THey did not come with screws. My question: What length screw do I need for the installation of the window ring, with a wall 3/4" thick? Thanks