That is it you are done with the setup and you can now easily restart the browser without the fear of losing your tabs. This setting takes effect immediately without the need to restart your Firefox browser.
HOW TO RESTART FIREFOX WITHOUT LOSING TABS WINDOWS
Then press enter and it will just close all the browser tabs and will restart the browser again with all the tabs that are previously opened. Just copy and paste this URL into your browser’s search bar. For restarting chrome here is a quick URL that helps you do that and that is chrome://restart.