This simple circuit is supposed to toggle on and off a led light with a single button. At the start condition the led light is off; at the node 2 of the circuit the signal is high.
When you press the switch button the node 1 takes the high signal from the node 2, so both transistors switch on. Once the capacitor discharges through the collector of the Q2 transistor the node 2 takes the low signal. When you press the button again both transistors switch off due to the low signal from the node 2.
This circuit works properly if the button is pressed for two seconds or less.