You can select the Devices link found at the bottom of the app home screen. You will be provided with a view of all the devices that are connected to your network, and a list of devices that are currently disconnected from the network.
The device list is organized by the type of password being used. Ethernet-connected devices will appear in the Home zone.
From here, you are able to tap on each individual device to view networking information such as the device's MAC address, and IP address. You have the option to rename your device when you tap on the device image. Devices can also be assigned to people or assigned to a room if you are using Plume Motion.
Normally a device will stay in your device list for 14 days after they last connected, at which point they'll drop off. If the device is assigned to someone, however, it will stay listed even if the device hasn't been connected for more than 14 days.