After you have Prepared your devices and have set the Supervise setting to ON, you can further manage them within the Supervise icon.
You can create groups and drag the devices into these groups. You can also add additional apps to the devices/groups. If you have installed paid-for Apps and uploaded the VPP .CSV spreadsheet with codes, you can track and see which devices are using which codes and how many you have left.
For in depth tutorial watch the video: