A flashcard gives you a small memory test. Read the prompt, try to answer, and then check the back. This shows what you can produce now.
Good cards ask one clear question. Use a short sentence, a useful sound, or a simple example. Give enough information to correct the next attempt, but do not fill the card with clutter.
Cards help you remember. Reading, listening, writing, and speaking help you use that knowledge in real life. Add new cards slowly enough to finish tomorrow's reviews.