Skandapurana 14.32.34

14.32.34

pūrvottare same deśe kṛtvā vediṃ ca maṃḍapam ..
madhye cāṣṭadalaṃ padmaṃ gṛhyasūtraṃ prayojayet ..34..

Having made an altar and a pavilion on level ground in the northeast, / and in the center an eight-petaled lotus, one should apply the domestic ritual manual;