Macro to open a workbook from an unknown file path

obviously not tested

Sub FindInSubfolders() ' main, call SubFoldersFind
   Dim StrFile As String, objFSO, destRow As Long, fname As String
   Dim mainFolder, mySubFolder
   mFolder = Range("B2").Value
   fname = Range("B3").Value
   macroname = Range("B4").text
   mdata = Range("B5").text   
   Set objFSO = CreateObject("Scripting.FileSystemObject")
   Set mainFolder = objFSO.GetFolder(mFolder)
   StrFile = Dir(mFolder & "\" & fname)
   If StrFile <> "" Then
      Workbooks.Open mFolder & "\" & StrFile
   Else
      SubFoldersScan OfFolder:=mainFolder, fname:=fname
   End If
   Range("A1").value = mdata
   nn = ActiveWorkbook.Name
   Application.Run "'" & nn & "'!" & macroname
End Sub
   
Sub SubFoldersScan(OfFolder As Variant, fname As String) 
    Dim SubFolder
    For Each SubFolder In OfFolder.SubFolders
       StrFile = Dir(SubFolder & "\" & fname)
       If StrFile <> "" Then
          Workbooks.Open SubFolder & "\" & StrFile
          Exit For
       End If
       SubFoldersScan OfFolder:=SubFolder, fname:=fname
    Next SubFolder
End Sub