This getting started guide video only applies to Signal Owl firmware version 1.0.0. From version 1.0.1 onwards, entering arming mode is accomplished by pressing the button any time during attack mode (roughly 1 minute after power-on). Continue reading.
Version 1.0.0 Note: In Signal Owl firmware version 1.0.0, entering Arming Mode was achieved by momentarily press the button during a 3 second mode selection phase at bootup which was indicated by the rapidly blinking LED.