Autofilter When Workbook Opens

My workbooks contains 2 worksheets with data and autofilters on for each column in use.

When my workbook opens I am trying to reset the autofilters of each worksheet in the workbook and to filter the data according to one criteria in one column.

This is what I have that works to reset each worksheet but I haven't been able to figure out how to subsequently filter each worksheet.

Private Sub Workbook_Open()
Application.ScreenUpdating = False
For Each w In Worksheets
w.Unprotect
If w.FilterMode Then w.ShowAllData
w.Protect DrawingObjects:=True, Contents:=True, Scenarios:=True _
, AllowFiltering:=True
Next w
Application.ScreenUpdating = True
End Sub

The autofilter sits in A3 to N3 and I am trying to filter according to column M (i.e. 13th column)