What does 2 Kings 22:1 mean?

Josiah was eight years old when he became king, and he ruled in Jerusalem for thirty-one years. His mother was Jedidah, daughter of Adaiah from Bozkath. 2 Kings 22:1 - Modern Text Bible

(Josiah starts ruling as a child, and his long reign is introduced. His mother’s name and hometown are given, which was common for royal records.)