Sign In and Play - allows you to login into your PlayStation Network account temporarily on this console.
Get Started - for creating permanent accounts on your PS5.
It doesn't matter how you reach this option, because, once you do, you'll always be brought to the same screen which offers you three options:
The 'Users and Accounts' submenu in the console's settings.
From the Control Centre accessed by pressing the PS button.
The 'Switch' User' option from the home screen.
From the user select screen that appears when you boot up the console.
If you want to create a new account on your PS5, you need to select the option 'Add User.' This option is easy to access and can be done so in a number of ways: Watch on YouTube How to add new accounts to the PS5