Get Your Hardware in Order.
To build all most anything, you need to use hardware. If you get the order wrong, it may fall apart. This is the correct order of things. If you have a self locking nut, you can skip the lockwasher. The self locking nut has a nylon collar inside, which grips the threads. Using Loctite on the threads also helps keep things from falling apart, and can be used with a regular nut.