I’m very new here and love that I can go through the flash card style of Japanese letters, but I’m a slow learner and need repetition. How do I go back into the flash card style of studying and take the quizzes over and over again?
Welcome! I'm not aware of any way to review past quizzes, but you can study the letters you learnt again using the 'Focused Review' button (only available after you've finished learning/reviewing today's letters - if there's too many new ones you can reduce this in the schedule settings). The letters you studied today will also periodically return for review, so if you log back in tomorrow they'll be there as a new quiz to study.
You can have a summary at the end of your quiz, but quizzes themselves are not set in stone. They're randomly generated.
You can just keep repeating quizzes, and just keep the schedule size small so you can practice the same stuff at a time to drill a lot on those areas, but you can't review a quiz itself unless you've ended the quiz.
You can only otherwise review what's in the schedule or practice through the quiz.
The flashcard style is only when you learn new terms. Everything that comes after is reviews, which are scheduled based on if you do them correctly. If you really want the flashcards, I guess you could search them in the dictionary or advanced search them and mark them as unknown (the lightbulb), although that's not recommended. Like the others said: quizzes are randomly generated, and there's no way to repeat the exact same quiz. You just have to be patient. The terms will come op tomorrow or the day after, and the more you answer them correctly, the longer the gap between them popping up becomes. For now, just learn new terms at your own pace, and the reviews will get back at you in the next few days.