Numbers 10:6

When ye blow an alarm the second time
Another "tara-tan-tara":

then the camps that lie on the south side shall take their journey;
the camps of Reuben, Simeon, and Gad, which were encamped on the south side of the tabernacle, ( Numbers 2:10 Numbers 2:12 Numbers 2:14 ) ; and, as Josephus ^F11 says, at the third sounding of the alarm, that part of the camp which lay to the west moved, which were the camps of Ephraim, Manasseh, and Benjamin, ( Numbers 2:18 Numbers 2:20 Numbers 2:22 ) ; and at the fourth sounding, as he says, those which were at the north, the camps of Dan, Asher, and Naphtali, ( Numbers 2:25 Numbers 2:27 Numbers 2:29 ) ; which, though not expressed in the Hebrew text, are added in the Septuagint version, as they are to be understood:

they shall blow an alarm for their journeys;
for the journeys of the said camps, as a signal or token when they should begin to march.