You can change the UCP system model type from hyperconverged to rack-scale to add storage devices.
When you configure a hyperconverged UCP system, the storage icon is disabled because this system does not include storage systems. However, if you later determine that you want to add a storage system, you can do so by changing the UCP system type to rack-scale. After you make this change, all the existing devices, and the system serial number are migrated from the hyperconverged system to the rack-scale system.