You can attach these modules yourself without any tools or help and brackets mount them to a wall as per your requirements. It's a German concept and the prices start from 22 € for a CD24 module. You can install these modules at places where a normal cabinet would be difficult place like under the stairs or behind the doors.
You can take help from an online configurator to design your custom layout. You can start with one cubit and slowly buy more pieces to create a complete shelf. A revolutionary idea in the world of storage.