If you click on the CMDB you cannot add the "Customized Colum" with the field "Serial Number".
Please add the Serial number in the Overview of the CMDB please.
See screenshot for further details.
When installing disk it asks for serial number I entered the number given me on the sleeve of the cd. It then tells me invalid serial number
Serial number cannot be added on the default "All Assets" view, yet. I'll add this to our backlog.
Meanwhile, you can create a custom view for Hardware type and then add serial number as a column. You can find more info on this here.