Assuming you are talking about the floor charger for an electric vehicle:
Most floor chargers come with a cord that has either a J1772 or Type 2 connector. To start charging, first make sure that your car is properly connected to the charger. Once everything is plugged in, the charger should start automatically. If it doesn't, consult your car's manual or the charger's documentation to see if there is a power button that needs to be pressed.