The diy breathing device ebook download does NOT contain any instructions to make the breathing device. I have downloaded several copies of this ebook and NONE of them contain any instructions. The pages from 41 to 61 are missing, apparently where the instructions would be, and there is no indication of where to find the missing pages or instructions.
Also there are no instructions on how the breathing device works.
I found elsewhere that the Frolov instructions suggest starting with 2 second inhales and 5 second exhalations, then gradually extending this by 1 second per day when accomplished. The exercise is done from 5 to 20 minutes depending on current fitness and condition. Athletes are able to progress more quickly and to perform the exercise for longer periods. As the exercise ability improves, the circuits can be increased (by 1 second a day) to 2 second inhales, and 10 second exhalations. An advanced level would be to reach 28 second exhalations for 20 minutes of the exercise. My understanding is that you do not need any device to do this exercise, as you can just do the exercise with a watch or without one.