Four breaths per minute is, of course, just a guideline. I take fewer breaths per minute. The idea is to take deep breaths very slowly before starting. So you are encouraged to adjust that rate. Also, with your eyes closed, try focusing on an imaginary or physical point during stillness. It will help you focus. When learning to still your mind, initially, even five minutes may seem like half an hour. However, if you persist, you will be able to focus better and sit still for a longer period at a time. In stillness, all things can be known. I have experienced timelessness in stillness. I wish for everyone to be able to experience that indescribable state.