Shipping containers can be coupled using a twist-lock coupling mechanism. A twist-lock is a metal device that is attached to the corners of the containers and locks in place when it is twisted.
To couple containers together, they must first be placed on a suitable surface. Then, the twist-lock is attached to the corner of one container, and the other container is positioned opposite it so that the twist-locks of both containers are facing each other. The containers are then pushed towards each other, so that the twist-locks can be twisted and locked together.