I do not understand too much about how to handle .csv files in Excel

this will prevent the display alert
Code:
 Wb2.Save
 Let Application.DisplayAlerts = False
 Wb2.Close
 Let Application.DisplayAlerts = True
 Wb1.Close
But it may not give the results you want.

I do not understand too much about how to handle .csv files in Excel
There may be complicated issues to do with internal settings.
Opening and closing csv files in Excel might involve lots of complicated work. I do not have much experience in this work.