In a clean spot, prepare a stable seat for yourself, neither too high nor low, spreading kuśa grass, a deer skin and a cloth, one over the other.
How well in detail does Krishna instruct the procedure for meditational sitting!
The practitioner should first select a suitable, clean spot, wherever available. Then he should prepare a seat exclusively for meditation. It should be stable and strong. It should not be disproportionately high or low. He must feel comfortable and encouraged.
In case it is a spot on bare ground, the āsana has to be protected from white ants. Hence Krishna prescribes it must have three layers. The first of kuśa grass, used by priests in Vedic rituals. Over it is a deer skin, a mark of gentleness and tolerance. Lastly a cloth to sit on. This can be washed periodically. All the three together form an ideal seat for meditation.
Do not make the āsana (seat) too soft and luxurious. The whole body must have proper and nourishing blood and air circulation, without numbness. Be clear that meditation is aimed at sharpening your attention.