You can get only so far with your scripts by working with field values. Eventually you need to deal with more than one record. Thankfully, FileMaker has script steps for creating, duplicating, and deleting records; navigating among existing records; and even managing the process of opening and editing a record, and saving (committing) or reverting the changes. You can also work directly with portal rows on the current layout—and the records they represent.
New Record/Request and Duplicate Record/Request have no options, and do exactly what you'd expect. The first script step creates a new record, just like the Records → New Record menu command. The second duplicates the current record. In either case, the new record becomes the current record, just like when you do it manually. You use these steps most often on buttons, when you're taking away menu commands from people and providing them with buttons that appear only on the layouts where you want your users to be able to create records.