I was going to say 3rd screen for settings could be used. But, there is the windowed mode with the empty space in the upper left side. There is plenty of room there for settings like Insomniac mode(aka allNight), snooze settings, etc.

I think a button for instructions on the main page would be kind of annoying. It would take up valuable screen space for something that would only be needed once. An option could be an instruction video/slides with illustrations that demonstrate how to use the application. Then give the option to not show that video on start up. A button could be placed in one of the settings screen to relaunch that "manual" so the user can read up on all the features.