It is not as simple as just code as it also uses a Public Variable which once set by the password routine can then be used anywhere in the database, ie to allow access to forms and record what users do with the data etc.
So here is a copy of the database with the tables and forms that control the users and their passwords.
There are Modules in it with useful VBA code as well.
There is also the basis for recording who makes what entries in the database including changes to data already entered.
When the database opens Select Administrator and enter tony as the password and it will open a dummy form called First Form.