At the start condition both transistors and the led light are off, so at the node 2 we have a positive signal.

By pressing the button the high signal is sent to the node 1, so both transistors conduct.

The signal at the node 2 becomes low when the capacitor discharges on the collector of the Q2 transistor.

By pressing the button again the low signal is sent to the node 1, so both transistors get off.

This circuit works properly if the button is pressed for one second or less.