potentially a daft question incoming :D

I dont understand how i can get the code to work upon opening the sheet.

If for example the usernames i want to be able to open the spreadsheet are:
Dduck
Wcoyote
Bbunny

then how do i incorporate that into the 
Private Sub Workbook_Open()

End Sub
Either with those usernames being hard coded into the macro or with the usernams being entered into a sheet within the workbook?