The Buddha once said this to the Bhikkhus:
"Bhikkhus, as to the source through which perceptions and notions tinged by mental proliferation beset a man: if nothing is found there to delight in, welcome and hold to,
ZAZEN MEDITATION GUIDE - Chapter 9. Choosing the Place to Sit
It will be best if you have a private room in your house. If not, you will need a separate corner to do zazen.
You might like to have a small statue or a picture of the Buddha or Bodhidharma or some other Zen master whom you like. Or if you like, you can do palms together and bow or do prostration (three times for each) before the statue.
When you do either of these, just do it and do not think you are asking any favor from them or "Why do I have to pay my respect to these statues?"
If you start thinking of something like that, then it is just your ego's action. The statue or picture can be hung on the wall or placed on your desk. A couple of sutras like the "Heart Sutra", the "Diamond Sutra", the "Platform Sutra of Hui-neng", or alternatively one of a selection of Zen mastersâ€™ records like Joshu Zen masterâ€™s Record, or any other Zen masterâ€™s you prefer.
If you like to have some sandalwood incense to burn or some kind of flower in a little vase, it would be fine. All of these will give you an atmosphere of dignity to do zazen.
The room or the corner should be not too dark or too bright when you sit in zazen. The temperature is not too hot and not too cold; if you can have some kind of clean and fresh air, it would be ideal for a rather long period of time. All of the above mentioned will make up a simple and serious atmosphere to zazen.
You will need to face a plain wall or curtain from about a distance of about one yard. Your eyesâ€™ sight is neither set up high nor low. Your eyes should be just half-closed and alert. Your tongue-tip might be set lightly against the upper palate close to the upper teeth.
Note: Do not sit on a bed or a couch, except if you are sick or cannot move yourself.