First March Numbers 10

Numbers 10:2 "Make thee two trumpets of silver; of a whole piece shalt thou make them: that thou mayest use them for the calling of the assembly and for the journeying of the camps."

A signal is planned so that the congregation will know what to do and move as a single unit. The trumpet is used to give the signal with different blast used for different task to be performed.

Next the order of the march is set up i.e. who goes first, where is the tabernacle in the march and etc. I've made a list if I got it right: Judah, tabernacle, Reuben, Simeon, Gad, Sanctuary, Ephraim, Manasseh, Benjamin, Dan Asher Naphtali. So as I see it, Judah would move out and then comes the tabernacle with the ark and so on.

So with the order of march and the signals Israel goes on their first march:

V33 "And they departed from the mount of the Lord three days journey: and the ark of the covenant of the Lord went before them in the three days' journey, to search out a resting place for them."

Psalm 127:1 "Except the Lord build the house, they labor in vain that build it: except the Lord keep the city, the watchman waketh but in vain."