Device pool creation can be accessed from the Devicepool page.

Here you can create a device pool to group your devices in.

Here simply enter the name of the device pool and click submit.

In the 'Devices' tab, all the devices within the device pool are displayed. You can click and hold to drag the device panel which will allow you to reorder devices in the list. Reordering this will change the order of which devices are displayed on the dashboard page.