A brief overview of the story is that Josiah is reigning (righteously) and is brought the book of the law that had been lost. He rent his clothes because of the sorrow he felt after he heard what the book said. He realized how wicked his people had become, and sorrowed as the ramifications for his people sunk in. He personally was humbled and repented of his sins. He went forth destroying and defiling the shrines and other "holy" places the people had for their false idols and preached the law to the people.
Without the scriptures, and regular study of them, you forget what they contain. I mean, there are a TON of pages and so much that is covered. When you dedicate time daily to the study of them, your life will be filled with the spirit of Christ, burdens will feel lighter, you will receive the insight you prayerfully seek, and you will know what the Lord expects of you.