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:
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 the mouse. If you want to make both fields editable with a single keystroke, press Ctrl+E.
See also:
Remember! The place where your new items are added in the knowledge tree is determined by the default concept group, not the current selection in the Contents window.