Joshua 8:10

and you shall rise up from the ambush, and take possession of the city; for the LORD your God will deliver it into your hand.

It shall be, when you have seized the city, that you shall set the city on fire. You shall do this according to the LORD’s word. Behold, I have commanded you.”

Joshua sent them out; and they went to set up the ambush, and stayed between Bethel and Ai on the west side of Ai; but Joshua stayed among the people that night.

All the people, even the men of war who were with him, went up and came near, and came before the city and encamped on the north side of Ai. Now there was a valley between him and Ai.

He took about five thousand men, and set them in ambush between Bethel and Ai, on the west side of the city.

So they set the people, even all the army who was on the north of the city, and their ambush on the west of the city; and Joshua went that night into the middle of the valley.