Sign in field values (login, password)

Hello there. My question is how to set up login id and password field values that need to be automated?
After starting field configuration, and selecting the text box for login field, i select ‘Action’ as ‘Set value’ but it asks me to provide ‘Input source’ and the list there is empty.

Is there any demo video or explanation for step by step automation of login process?

Thank you


Login Id and Password field will come when you create a sign in process