Hi Chris, if you are still using the stock launcher, you may be unable to find an option to manage home screens. The default setting has the third screen as the home screen of the phone, so pressing the Home button will thus always bring you back to it. If you need to have certain apps or widgets within reach, then just place them onto the third screen. Alternatively, you can also download and install a third-party launcher like Apex Launcher or Nova Launcher in order to make the option of managing your phone's screens available. You can find either of these at the Google Play store. Let us know if you need any more help!