Sub Main()
Dim oAsmDoc As AssemblyDocument 
oAsmDoc = ThisApplication.ActiveDocument  
Call Iterate(oAsmDoc.ComponentDefinition.Occurrences, 1)
End Sub 

Private Sub Iterate(Occurrences As ComponentOccurrences, Level As Integer) 
'Iterate through Assembly

Dim oOcc As ComponentOccurrence 
For Each oOcc In Occurrences 

'Find Parts in Assembly
Dim CadlinePart As String
CadlinePart = oOcc.Name
Try 

'Write iProps to Parts
iProperties.Value(CadlinePart, "Summary", "Comments") = "Hello World"


Catch
'MsgBox("Message!")            
End Try
        
'Run through the sub assemblies 
If oOcc.DefinitionDocumentType = kAssemblyDocumentObject Then
Call Iterate(oOcc.SubOccurrences, Level + 1) 
End If 
Next 
End Sub