You can add new devices here and configure the calls on the devices according to your usage.
To add new devices, click on "Create New".
Select the device from the drop-down menu, for example: Grandstream, Yealink, Cisco,etc.
Next, select the device model and enter the MAC address of your device in the textbox.
Select the Line number and extension for the device.
You can add more lines and extensions to the device. Just select the device and click on "Add Lines", and Save the changes made.