The Yellow Mongoose model does not require a Wi-Fi dongle: if you create your location via the BlueFox count app, disregard the step of plugging in the Wi-Fi dongle to your sensor.
The device connection to a Wi-Fi network can only be set via the mobile app.
Note- When configuring the Wi-Fi, the SSID broadcasted by this sensor is going to be slightly different from the other BlueFox sensors; it still starts with @BLUEFOX_ but the pattern of the numbers would be different from what's specified by your app.
Also, note that the 3 LEDs are white and any reference of red/green LEDs in general documentations does not apply to this sensor model. However, the blinking pattern remains the same.