How can a student of knowledge review fiqh issues, learn about the opinions of scholars and schools of thought, and identify what is most correct (rajih), what is agreed upon, and what is differed upon? And what are the recommended books for researching this, while making use of Al-Maktaba Al-Shamilah program?

The first step is to consult a jurist (faqih) and study with him the concise books of fiqh (Islamic jurisprudence) from one of the madhhabs (schools of thought), then gradually progress in your studies. After that, you can refer to books such as "Bidayat al-Mujtahid," "Al-Mughni," "Al-Majmu‘," "Nayl al-Awtar," and "Al-Mawsu‘ah al-Fiqhiyyah" (The Jurisprudence Encyclopedia) to understand the differences among the imams, their evidences, and the preponderant opinion. If the truth does not become clear to you, then recite the supplication mentioned in Sahih Muslim: "O Allah, Lord of Jibreel, Mika’eel, and Israfeel… Guide me regarding that wherein there is disagreement concerning the truth, by Your permission, for verily You guide whom You will to a straight path." Then, seek assistance from trustworthy contemporary scholars to ascertain the preponderant opinion.