In order to use a DPC Code to install Ensemble onto your device, you will first need to navigate to your Devices page, and then be sure that the selection at the top of the page is set to "During Setup Wizard". This is what you should see:
In order to use the DPC Code, the device must either be fresh out of the box, or factory reset and not currently on your company assigned to a project.
When you have your device in hand, move through the initial setup wizard as normal. Be sure to connect the device to an available WiFi or cellular network, as this is required to download Ensemble onto the device.
Once you get to the Google sign in page, you will want to type in the DPC Code from the Devices page, rather than a Google account.
After typing in the code to the field and clicking Next, proceed through the rest of the setup wizard as normal.
You will need to confirm the installation of Ensemble, and once you are through the wizard, Ensemble will be installed onto the device.