Typically, each apparatus would be linked by a string or ramp to its predecessor and successor machine. The initial string would be ceremonially pulled, and the ensuing events were videotaped in closeup, and simultaneously projected on large screens for viewing by the live audience.
In general, each device is linked to its predecessor and successor via a string or ramp.  The first string is pulled ceremoniously, and the ensuing actions are captured in close-up and shown on large screens for the live audience.