Once the program is running, your whole screen turns light green (although you can change this tone as desired) and you can start writing with no windows, options, or apps in sight. That way, you can concentrate better and write without having to keep track of anything but your text.
But just because it's minimalist doesn't mean it doesn't have possibilities. If you right-click on your screen, you'll access loads of different options to make all kinds of different tweaks (change fonts, background color, insert items, etc.).
Monkey Writer is a very useful tool that lets you write without any complications, which is a real pleasure.