Tosefta zu Bamidbar 3:52

How would the elders sit? They would face the congregation and have their backs to the Holy. When they set down the Ark, [the elders] would face the people with their backs to the Holy. When the Kohanim lifted their hands, they would face the people with their backs to Holy. The prayer-leader of the congregation faces the Holy and all the people face the the Holy, as it says (Lev. 8:4), "And the assembly was gathered at the entrance to the Tent of Meeting." We do not open an entryway to a synagogue except toward the east, as it says (Num. 3:38), "Those who camp before the Tabernacle, to the east, before the Tent of Meeting, to the west." We do not build [a synagogue] except at the highest point of the city, as it says (Prov. 1:21), "At the head of the thoroughfare she (i.e., Wisdom) calls."