Button Add new at the bottom of the screen makes it possible to add new questions and answers to your collection:
To complete your item: (1) type the question, (2) press Esc to move to the answer field, and (3) type the answer. Press Esc again to finish changing the newly added question-answer pair.
You can jump between the question and the answer by choosing Ctrl+T. If question-answer fields are inactive (e.g. after pressing Esc a few times), you can edit the question by pressing Q or edit the answer by pressing A. You can also start editing by a mouse click.