APOLOGETICS

"Apologetics is the religious discipline of defending religious doctrines through systematic argumentation and discourse. Early Christian writers who defended their beliefs against critics and recommended their faith to outsiders were called Christian apologists. In 21st-century usage, apologetics is often identified with debates over religion and theology." Remember that many non-Catholics are sincere in their beliefs and in their search of Truth. All such discussions must always remain respectful. It is best to explain why we believe what we believe. Detailing the errors of others is counter=productive.
Read books, and attend Catholic Religion Education Classes - led by a knowledgeable person. Facts are important. Opinions* - not so much. * Opinions are a view or judgement about something , not necessarily based on facts or knowledge.