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.
You can jump between the question and the answer by pressing Ctrl+T. If question and 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 them with a click of a mouse.