The three green LED lights go on as the Business starts up and establish basic functionality.
The Power light indicate if the device has been powered. If it's not emitting light, you might want to check and make sure that the DC adapter is inserted fully into the device as well as the power outlet. Also, some buildings have the power supply wired to a light switch and/or automated control, which might result in power loss.
The cloud icon indicate if the Hub has an active internet connection with the Airthings cloud. Upon start-up, it may take a couple of minutes to establish connection. If it's not coming around to get lit, there may be a problem with cellular coverage (4G Cat-M1) or local ethernet settings (if ethernet cable is used). We have more troubleshooting details here: https://help.airthings.com/en/articles/4350753-airthings-for-business-connection-issues
The SmartLink Connection icon indicate if there are any sensor devices connected yet. After internet connection has been established, it should only take a couple of minutes for the sensor devices to find the hub and connect. For devices with older firmware, it may take up to 8 hours before sensor devices connect fully.