Open the package
You should have the brass armature, electrical cord, a pull string, 2 screws, and a zip tie. You will need a small phillips screw driver, a pencil, scissors, and a hardcover book.
Selecting the right kind of book
The book should be roughly 9 inches tall, 6 to 7 inches deep and about an inch and a half thick (about 400 pages). The book must be a hardcover with a separated spine. This means when you fold back the covers, you should see daylight through the spine. Older, worn in books tend to work best.
Find a spot for the Secret Passageway Switch
Determine where on your bookshelf you want you switch to be. Near an end is usually best for concealing the wires later. Keep in mind you will need to run an electrical cord down the back or off to the side. Mark the desired location with the pencil and remove the books.
Attach the electrical cord
Unscrew the switch cap, place switch on the brass armature, reattach switch cap, zip tie off of the electrical cord, cut off excess zip tie.
Cutting the string to size
Measure the height of your book, with the armature open to 90 degrees, attach the end of the string to the pull chain, tie off the other end of the string to the armature, cut off excess string, un-attach the string from the pull chain. Note: it is a good idea to initially cut the string a little longer than you think you need, you can trim later.
Mounting the armature
Using the pencil marks you made earlier, line up the armature in the desired spot. Screw the armature down. Hide the wire and plug it into the wall.
Attach the book to the switch
Feed the string and armature through the spine of the book. Open the book to the middle page, attach the string to the pull chain, close the book.
Place other books back on the shelf next to the switch. Make sure it is not too tight and the book can move easily. Plug what ever you like into the switch's plug and you're done.