Configure Framework Defaults - difficulty with wording in the guides

I am upgrading to 6.1

The guides have the following wording.

To allow you to upgrade to new defaults one by one, the update task has created a file config/initializers/new_framework_defaults.rb . Once your application is ready to run with new defaults, you can remove this file and flip the config.load_defaults value.

and the guides say: config.load_defaults loads default configuration values for a target version and all versions prior

So when I ran app:update config/initializers/new_framework_defaults_6_1.rb was created. But if I am going to delete this file, should I put the suggested defaults into an existing file. If that is the case why would I then need to flip the config.load_defaults value. I am somewhat confused about what I should aim for as the final state

The new_framework_defaults file allows you to flip each feature listed therein On, one at a time, while you are testing your app (started in the previous version’s defaults). So if your application.rb starts under 6.1, then you would uncomment each of the configuration options in the defaults file, restart your server, test interactively (and also run your test suite). Once you have cleared all of the options in the defaults file, and everything still works, you can change the load_defaults value to 7.0 AND remove the new_framework_defaults file. They go hand-in-hand.