These are intended to be used in AC distribution boxes where they clip on to a DIN spec rail behind them. You can use them outside a distribution box by fitting wires into the top and bottom holes then clamping with the screws. Be careful, they are not designed to be reachable under normal circumstances and they are not to be used as power on/off switches or in DC circuits. Also note it is rated to open 'trip' only when more than 32 Amps flows through it, that equals as much as 8KW of power !
Brian.