What are the simplified topics that would help a Christian friend in Europe understand the details of the Islamic religion?

The Noble Qur’an can be translated for non-Muslims, focusing on the Five Pillars of Islam, starting with Monotheism (Tawhid), then prayer (Salat) and charity (Zakat), as mentioned in the Prophet’s (peace be upon him) hadith to Mu'adh (may Allah be pleased with him). Available resources for non-Arabic speakers can be utilized.