I cut a piece of sheet metal to fit between the walls of the stable and cut some decorative paper the same size. Glue the paper to the metal and the metal to the floor.
While that is drying you can cut the small pieces of the sheet magnet and glue to the bottom of the figurines. Trim off any excess magnet around the edges.
Next to have the little angel perch on top of the roof. I cut a small piece of metal painted one side brown (so it blends in with the branches of the roof) and glued it to the centre beam towards the front.