You can edit a local project (click "Open Local Folder"), a Dropbox folder ("Open Dropbox Folder") or the built-in Notes, Configuration and Manual projects. None of those work? Works fine my my Chromebook.
Even after making the window big enough so I don't have to scroll, this is all I see:
I can either enter a Project or a URL to edit. Typing text in either place does nothing interesting. "Enter" does nothing.
Clicking around, I can't find any way to make a new window. All I want to do is see your editor and start playing with it. I don't even really want to edit a file yet. No obvious way to make any of that happen.
The first window is too small. The note about how to edit remotely requires scrolling, but it isn't obvious that the page needs to be scrolled.