Remove the back and glass portions of the frame.
Lay the empty frame on top of the wallpaper; trace around the outside of the frame edges using the pencil to create a cutting line.
Place the wallpaper on the cutting mat and cut along the pencil lines using the utility knife.
Arrange the collage elements on the wallpaper as desired, and glue down onto the paper using the veneer glue. Allow the collage to dry.
Attach the collage to the wall in the desired position using a layer of wallpaper glue applied with the foam brush. Press the collage firmly, and smooth out any air bubbles.
Apply a generous amount of wood glue to the backside of the frame. Center the frame over the collage, matching the edges of the collage with the edges of the frame, and press frame against the wall. Allow the glue to dry.