Did you take a look at 'SD.IncidentManagementSimple.Classification'?
Look at the 'Update Incident Data' mapping
Create a Decision Project Type
Pass in a IncidentSessionId as an Input
Use the 'Get Incident Ticket By SessionId' (Symantec.ServiceDesk.Im.Core.Components.GetIncidentTicketBySessionId) to get the Incident Data
Build up your Classification (Hardware.X.Y) based on your logic for a given ticket type or however you want to assign,
Use a 'Single Value Mapping' (LogicBase.Components.Default.Mapping.SingleValueMappingComponent) to map in the Classification
Save Incident Ticket (Symantec.ServiceDesk.Im.Core.Components.SaveIncidentTicketComponent)
Save External Data (LogicBase.Components.Default.Process.SaveExternalDataComponent)