The Home icon on the top left corner of the home screen means that you are connected to the Wifi.
The Tower icon below the Home icon on the top left of the home screen is used to change the audio output route. You can change it to your iPhone’s normal speaker, an external speaker, etc.
The Green dot on the top left corner of the home screen tells you whether your feed is live or buffering. If the Green dot is blinking, that means that you are watching the live feed of your baby. If the green dot is not blinking, that means that the live feed is either buffering or is in a non-streaming state.