Moses, Aaron, and Aaron’s sons were to camp to the east of the tabernacle, toward the sunrise, before the Tent of Meeting. They were to perform the duties of the sanctuary as a service on behalf of the Israelites; but any outsider who approached the sanctuary was to be put to death.
Jewish Publication Society of America Version (JPS1917) - Numbers 3:38 >And those that were to pitch before the tabernacle eastward, before the tent of meeting toward the sunrising, were Moses, and Aaron and his sons, keeping the charge of the sanctuary, even the charge for the children of Israel; and the common man that drew nigh was to be put to death.