If you have a test server available or any other server that’s not the same server as the one you’ve created the backup from, then you should be able to “restore” the backup file on the test server.  Use SQL Server Management Studio to view and open the contents of the newly restored database.  Using another server would prevent you from overwriting your production database, granted that the database does not also exist on the test server.

I hope this information is helpful.

You don't open a .BAK file. You use it to:

1) Restore on top of your damaged or corrupted database

2) Restore to another server, for example to developement from production

3) Restore to the same server, but with a different name, for example to retrieve specific data

etc ....