The armed guard marched ahead of the priests who blew the trumpets, and the rear guard1 followed the ark. All this time the trumpets were sounding.
References for Joshua 6:9
But Joshua had commanded the people, "Do not give a war cry, do not raise your voices, do not say a word until the day I tell you to shout. Then shout!2"
References for Joshua 6:10
So he had the ark of the LORD carried around the city, circling it once. Then the people returned to camp and spent the night there.
Joshua got up early the next morning and the priests took up the ark of the LORD.
The seven priests carrying the seven trumpets went forward, marching before the ark of the LORD and blowing the trumpets. The armed men went ahead of them and the rear guard followed the ark of the LORD, while the trumpets kept sounding.
So on the second day they marched around the city once and returned to the camp. They did this for six days.
On the seventh day, they got up at daybreak and marched around the city seven times in the same manner, except that on that day they circled the city seven times.3
References for Joshua 6:15