You can start with something like this
It adds a sequential number to the file name in the Move
Option Explicit
Sub RenAllFilesInclSubFold()
Dim oFSO As Object, oFolder As Object, oFile As Object
Dim sPath As String, sName As String, sNewName As String
Dim N As Long
sPath = "C:\temp\OnBaseBackup" ' ----- initial folder that contains all the subfolders
'ren files in subfolders
Set oFSO = CreateObject("Scripting.FileSystemObject")
Set oFolder = oFSO.GetFolder(sPath)
N = 1
For Each oFile In oFolder.subfolders
'the files i want to rename and move, start with "inde"
sName = Dir(oFile.Path & "\inde*", vbNormal)
Do While sName <> ""
sNewName = sName & "-" & Format(N, "00000") & ".txt"
Name oFile.Path & "" & sName As oFile.Path & sNewName
oFSO.MoveFile Source:=oFile.Path & "\" & sNewName, Destination:="C:\temp\OnBaseResults" 'this code will not create the new folder
N = N + 1
sName = Dir
Loop
Next
End Sub