Start with a short philosophy text such as Philosophy of Religion: A Very Short Introduction by Tim Bayne, then pair it with a broader theology introduction such as Theology: A Very Short Introduction by David F. Ford. These are candidate resources for preparation, not official Cambridge recommendations.
For scripture and historical context, Introduction to the Old Testament (Hebrew Bible) and Introduction to the New Testament History and Literature give structured lecture routes into Hebrew Bible and New Testament study.
To broaden across traditions, the HarvardX courses Christianity Through Its Scriptures, Buddhism Through Its Scriptures, and Islam Through Its Scriptures are useful because the Cambridge course can move between scriptural, historical, philosophical, and comparative approaches.
For method and argument, use The Religious Studies Project, Philosophy Bites, and In Our Time: Religion to hear academic disagreement handled in a precise way.
For video, the University of Cambridge channel is useful for official Cambridge material, while Wireless Philosophy helps applicants practise philosophy-style argument analysis.
Keep a reading log with three columns: claim, evidence, and objection. That is especially useful for this course because interviews may involve an unfamiliar extract, image, quotation, or other stimulus that you need to analyse immediately.