Something like this …
Private Sub processFolder(ByVal oParent As Outlook.MAPIFolder)
Dim oFolder As Outlook.MAPIFolder
Dim oMail As Outlook.MailItem
For Each oMail In oParent.Items
'Get your data here ...
Next
If (oParent.Folders.Count > 0) Then
For Each oFolder In oParent.Folders
processFolder oFolder
Next
End If
End Sub