About altars and asans
Create the space in any way that has meaning for you. It may be a little spot to light a candle or have a picture of a saint or teacher or hold a stick of incense.
Your meditation area is also a place to keep an asan for meditation. The asan is a square of cloth, usually woolen, that is large enough to sit on for meditation. It can be twenty or thirty inches square or so, depending on your size. Anandi Ma recommends wool to maintain and build your energy over time and improve meditation, because it holds energy very well. If you are allergic to wool, silk or cotton can be used instead or placed over top of the wool asan.
An altar with photos of teachers, saints or deities can serve to inspire devotion while you practice and provides a place to offer flowers and incense, rest your mala, or light a candle.
An altar and an asan are not essential, but are supportive in building the energy and easing the mind into a state of meditation. Overall, whether simple or decorative, make a place that brings you a feeling of peace. A place that gives a sense of quiet and calm, where it is easy to settle in to meditate.