How should one read the Summa Theologiae?

Consider, for example, St. Thomas Aquinas on the topic of Mercy: [Question 30. Mercy](https://www.newadvent.org/summa/3030.htm) The **topic** is then broken down into a series of *articles* (questions) - which are further divided into Objections, **"On the Contrary"**, **"I Answer that"**, and **Replies to Objections**. Can someone provide a structural explanation of how one is to read St. Thomas Aquinas' *Summa Theologiae*; and in particular, how one is to determine which part of an Article's content reflect St. Thomas' personal thoughts on the matter? (e.g., Does St. Thomas himself always object to the objections? Are his true thoughts only found in "I answer that"? Are his true thoughts reflected in the "replies" to the objections?)