יהושע ח:ל פירוש: רש״י

Then [Yehoshua] built. This parasha is not in chronoligical order, [for Yehoshua built the altar] on the day they crossed the Jordan river.⁸Since the following verse states that he built the altar as Moshe had commanded them, we must conclude that this verse describes events that occured before the conquest of Yericho.