Use Yes Glue or a scrapbooking glue stick to apply paste to the back side of the stucco wallpaper and apply to the front side of the insert walls. Trim off excess paper with sharp craft knife. Paint the wallpapered walls the color of your choice - even though the paper is white it is painted prior to inserting into room box. Reason: When the fireplace is inserted there will be slight gaps where it meets the wall. You will fill these gaps with tacky glue and then paint to match the walls when the glue is dry - so thus - you need to paint the walls before inserting.