Don't be surprised if no one remembers how to use it correctly. They probably lost the manual years ago.
Ass goes on the grounded surface built into the chair (return)... hi pot lead goes onto the shaved head... usually a wet sponge is inserted into the skull cap that carries the lead, that improves the connection.
Resistance through the grounded body determines the current that passes ... and it's the current (amperage) that stops the organs and cause demise. Ohm's law (taught to every school kid once upon a time) says that voltage divided by resistance results in amperage. It takes less than one amp of current to kill a person dead, especially when it travels down the spine to the ass and passes the brain, heart and lungs on the way down.
Not much too it....