Wipe every last bit of dirt off the LCD and the frame. Make sure there are no fingerprints present.

Apply double-sided tape. This will help glue the glass onto the frame. I usually apply double layer before the camera and the speaker to prevent LOCA spilling inside them.

I also use backlight sealant to prevent LOCA from entering the backlight. A slim layer of transparent tape from .5mm on the LCD to the edge of the frame will also work.

You can go back later (remove the screen) and peel back the silver reflecting layer above the backlight and wipe the backlight clean, should any LOCA find itself inside the backlight.