This means that the tent of meeting must be carried by the Levites in the middle of the tribes as they travel.
# They must go out
"They" refers to the twelve tribes.
# by his banner
Each man does not have his own personal banner; rather, this refers to the banner belonging to his tribe. AT: "by his tribe's banner" (See: [[rc://en/ta/man/translate/figs-synecdoche]])