Launch Celtx and choose "Film" from the Project Templates list. This opens a new document with the toolbars and options pertinent to creating a screenplay.
Type your first scene heading into the gray strip at the top of the page. Your cursor will already be blinking inside of it. Because these gray strips are reserved for scene headings only, your text will automatically be formatted in that style.
Hit the "Enter" button. Celtx will insert the appropriate amount of space between the scene header and the next line and will change the style to the "Action" format.
Type at least one sentence of action and hit "Enter," then "Tab." Celtx will automatically change the style to the "Character" format.
Type a character's name, then hit "Enter." Celtx will change the margins as appropriate for the character's dialog.
Hit "Enter" again to re-enter the "Character" format or press "Enter" twice to enter the "Action" format.
Click the arrow at the corner of the "Styles" drop-down box to select any of these styles at any point. When you select a style, Celtx will automatically adjust the margins and caps as necessary to meet the industry standards for that style. Additional styles are also available to create parentheticals, transitions, shots and plain text.
Click the "Title Page" tab at the bottom of the screen to set up a title page for your screenplay. The template contains labeled sections where you may enter your information.
Click the "Save" button at the top of the screen to save your Celtx project. This is appropriate for saving your project for future use or for sharing your project with another Celtx user.
Connect to the Internet when you are ready to export your document as a PDF. This step is necessary to share your document with non-Celtx users, such as some producers and directors.
Click the "TypeSet/PDF" tab at the bottom of the screen. Celtx will create a PDF that maintains the screenplay format and conforms to the industry standards for screenplays.
Click "Save PDF" and select a location to which to export your screenplay.