On the home view (i.e., the Network tab), you can click on "Connected Devices" for either the 2.4GHz or 5GHz bands. Upon doing so, you will be presented with the list of connected devices operating in that frequency band. On this page, you can see whether the device is online (depicted by the green dot near the device's name), as well as whether the device is assigned to someone in your household and what the device actually is (e.g., a Google Chromecast).
By clicking on a particular device in this list, you are provided with more detail, including: Device Name, Owner, Manufacturer, Category, Internet Usage Today, IP Address, MAC Address. You are also given a snapshot at what the particular device's connectivity status and overall bandwidth consumption are. Lastly, you are able to pause the device by simply clicking on the pause icon at the top of the page. What this does is temporarily block the device from accessing the Internet, which can also be done through Parental controls.