Your drafts are automatically saved. Also, you can click on
Save in the editor and come back to it later. You can see all your videos - Drafts and Published, in the
Library of the respective workspace or your Personal Videos.
NOTE: If you regenerate a video upto 5 times in a week of its creation, it will not take up another credit but the 6the export will result in reducing your video count by one. However, you can create unlimited drafts and save, preview them for indefinite time without using any video credit.
Only once you click on FINISH to generate the video, the counter kicks in.