Snipe hinges (also known as cotter pin, or staple hinges), are the simplest and probably the earliest hinges used on American furniture.
They are installed as shown in this drawing. Each half is pushed through a hole drilled at a slant through the board from the back. The protruding points are spread apart, bent, and clinched back into the wood. Always pre-drill your holes. Wood splitting is likely to occur if you do not.