‘ And Joshua rose up early in the morning, and mustered (numbered) the people, and he and the elders of Israel went up before the people to Ai.'
As usual he rose early. There was a hard climb and they wanted an early start. Then the troops were mustered and set in their units. Then Joshua and his captains led the way up to a point near Ai, followed by their troops. ‘People' here clearly means men of war (Joshua 8:11).