Button Add new at the bottom of the screen makes it possible to add new questions and answers to your collection:
If you click Add new (or press Alt+A), SuperMemo will add a new item to your collection, and create two text fields: one for the question, and one for the answer.
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.
Remember! The place where your new items are added in the knowledge tree is determined by the default category, not the current selection in the contents window.