The generator works best when one file has a clear scope. A PDF chapter, a pasted transcript, or a vocabulary spreadsheet each become a coherent batch. If a source mixes unrelated topics, split it so each batch keeps a single learning target and a consistent card style.
For language learning, decide whether the Front should be the target word and the Back the translation, or the reverse. For exam material, decide whether you want definition cards, comparison cards, or mechanism cards. Setting that format once keeps the whole batch aligned, which is the main advantage of automation over ad hoc manual cards.