The first thing a Muslim begins with
What does the Shahadah mean?
The two testimonies are the foundation of Islam: you testify that none has the right to be worshipped except Allah and that Muhammad ﷺ is the Messenger of Allah, who must be believed, obeyed, and followed.
The meaning of “La ilaha illa Allah”
It means that worship belongs to Allah alone. Acts of worship such as supplication, seeking ultimate rescue, and worshipful reliance are directed to Him alone. It is not merely a phrase to say; it entails knowledge, certainty, truthfulness, acceptance, and submission.
The meaning of “Muhammad is the Messenger of Allah”
It means believing that Muhammad ﷺ is Allah’s Messenger to humanity: believing what he reported, obeying what he commanded, avoiding what he prohibited, and worshipping Allah only in the way he legislated.
Must I know everything before becoming Muslim?
No. Entering Islam begins with the two testimonies together with understanding and believing their meaning. A Muslim then learns prayer and the rest of the rulings gradually; a person should not delay Islam until becoming a scholar in every detail.
Sources
Supporting sources: official material from the website of Shaykh Ibn Baz linked by the Arabic source page.