‘ And afterwards he read all the words of the law, the blessings and the cursings, according to all that is written in the book of the law. There was not a word of all that Moses commanded, which Joshua read not before all the assembly of the children of Israel, and the women and the little ones and the strangers who walked among them.'
Then was made the solemn reading of the Law. This was probably the basic book of Deuteronomy, but may have included more. Included were both blessing and cursings, for this was all in covenant form, a reciting of what YHWH had done for them, a declaration of His requirements and then the blessings for obedience and cursings for disobedience (Deuteronomy 27:15-26; Deuteronomy 28 all).
This full reading of the Law was something that was required of Israel every seven years (Deuteronomy 31:10-13), although parts would no doubt be read out at all covenant festivals. Compare Exodus 24:7.
Thus having become first established in the land they solemnly renewed the covenant and incorporated within it all who had been willing to align themselves with them in the worship of YHWH. Then they returned to their camp at Gilgal (Joshua 9:6). All this would have taken a number of days.