Douban, IMDb and Letterboxd exports are easiest on a computer. No file at hand? Pick films you have seen; thirty give you a persona. Import later from a computer signed in to the same account and the records merge.
Import films and TV with automatic source detection. TV records retain their seasons; link unmatched shows yourself or send them for review. If you need an export file, check the guide first. Custom files require a title and year.