You may be using the wrong key. In a Scene Heading, Enter / Return takes you to the next line. The key you want to use to go from INT. or EXT. to location to time of day is the Tab key. After your location has been typed or selected from the SmartType list, Tab again moves to the time of day field in the Scene Heading. Once your entire Scene Heading is on the page, you can use either Enter / Return or Tab to take you to the next line.