I have the book but dont believe he specifies eyes open or closed, though when I listened to a guided meditation by him he advised eyes closed. I dont think it really matters as its what works best for you in your practice.
I also believe he states in this book to read through the different stages of his technique even if you haven't reached them yet so as to know what to expect and how to respond when you reach them.
The heart of the path is SO simple. No need for long explanations. Give up clinging to love and hate, just rest with things as they are. That is all I do in my own practice. Do not try to become anything. Do not make yourself into anything. Do not be a meditator. Do not become enlightened. When you sit, let it be. When you walk, let it be. Grasp at nothing. Resist nothing. Of course, there are dozens of meditation techniques to develop samadhi and many kinds of vipassana. But it all comes back to this - just let it all be. Step over here where it is cool, out of the battle. - Ajahn Chah