SB 11.27.19
sucih sambhrta-sambharah
prag-darbhaih kalpitasanah
asinah prag udag varced
arcayam tv atha sammukhah
Translation:
After cleansing himself and collecting all the paraphernalia, the worshiper should arrange his own seat with blades of kusa grass whose tips point eastward. He should then sit facing either east or north, or else, if the Deity is fixed in one place, he should sit directly facing the Deity.
Purport:
The word sambhrta-sambhara means that before beginning the Deity worship one should place all necessary paraphernalia nearby. In this way one will not have to get up continually to search for different items. If the Deity has been permanently installed, then one should sit facing the Deity.