Firebase authentication help

Hello. I have a Google Firebase authentication page (just an HTML login form) which already works successfully. What I want is after the successful login to have my main page appeared remaining on the same URL (redirected). On this page (main page) we are now, there must be a logout button. If we log out (press the button), then we go back in the initial login form (of course with forward chrome button not to be able to get back to the main page)

I want it today. So please do not give offers with 3 days or a week deadline.