Type using your keyboard. Only (minor) problem is that for key combinations, it results in the character as it would be on the standard U.S (I think) keyboard, e.g shift+9 is always "(". Shift and backspace work as expected. Arrows too, for navigation. Delete removes the currently selected line.
This is a typewriter meant to be as extendable and fast as possible, which is why it uses lists for displaying text. Might add some minor new features at some point. I'd like to make at least part of it pen-rendered so that the cursor marker thing can stop taking up space.