Pry off the baseboard molding with a hammer or pry bar. Since wainscoting covers the lower three or four feet of the wall, measure up from the floor 36 to 48 inches with a measuring tape, and mark with a pencil. Work your way around the room, marking as you go. Once finished, draw a line connecting all of your guidelines with a level to ensure a straight line.
Paint the upper portion of the wall if desired to contrast or complement your wallpaper, using a paintbrush. Paint down to the line you created, getting as close as possible.
Glue and apply the selected wallpaper according to directions, making sure all patterns line up and air bubbles are removed. Once you get the paper up to the guideline, trim it away with a utility knife, being careful not to cut into the wall.
Nail your selected chair railing directly over the guideline, covering the ends of both the paint and wallpaper. Hammer in one-inch finishing nails, countersink them and cover the hole with wood putty. Allow to dry, sand down until smooth and paint to cover putty.
Measure 36 to 48 inches from the floor, and create guidelines with a pencil. Mark around the entire room, using a level to ensure even, straight lines.
Paint the two portions of the walls in different shades or colors, using a paintbrush. If you want to use the same color, choose two shades. For example, if you want a green palette, use a darker green on the lower portion and a subtle mint on top. You may also use contrasting colors, such as a dark burgundy or brown on the lower portion, and a creamy white on top.
Apply the chair railing directly over the guideline, covering the two ends of the paint. Countersink the nails, and cover with wood putty. Allow to dry, sand and paint over to complete the project.