You almost certainly cannot submit it unfinished!
I suggest that you enter the entire thing before trying to preview. For matching quizzes, the preview only shows you the question and answer screen, so that information all needs to be there. You do not see the information in preview (at least, not at the moment - a change to the template has been requested, but it has not yet happened, and it may be too difficult for technical reasons), so all you would need to enter to see the preview screen would be your ten questions and answers.
If it still isn't happy, try typing "Information goes here." in the information box. The system will complain if you do not capitalise and finish with a full stop. You can then see the Q&A screen. Do not put anything in the Hint box, as it is not relevant for this quiz format.
If you still have no luck, try sending a message with the quiz name to an editor in the category where it is listed - they could try to have a look at it and see what might be going awry.
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(Editor in Humanities, Religion, Literature and For Children)
That's all, folks!