Please find attached a video showing the practice:
1) You pronounce the “A” very long in spirit, at the same time imagining that by pronouncing it in spirit it takes on a light blue color and in this color extends to the whole room. After some practice you will not only fill the whole training room with this mental “A”, whose light blue color must shine like a light, but the whole universe.
2) The student start again with letter “A”, appertaining to the air element, and conducts it to the air regions of the body, i.e., into the chest, where he pronounces it intellectually and imagines it to be there in a light blue color. Having imagined the existence of the light blue color in his chest for a longer period, he may resolve it again by his imagination. He must have the impression that the light oscillation of the blue color has completely disappeared from his chest.
3) You begin again with the first letter of the alphabet, with letter “A”, which now has not to be practiced in the whole region of the chest but in the lungs alone. The student transfers himself with his whole consciousness into each lobe of the lungs and feels and senses like a lung and does his exercises there. The “A” in its light blue color is again breathed in imaginatively from the universe into each lobe of the lungs and later again resolved into the universe.