Who founded Islamic civilization, when did the Islamic religion begin, what are its rulings, and how does an individual embrace it?

If the intent behind Islamic civilization is the material advancement achieved by the Ummah during its golden ages, then that began with Islam and developed with the conquests. However, if the intent is the beginning of the Islamic religion as a creed and law, then it began with the mission of the Prophet, peace be upon him, and its most important rulings are: the two testimonies (Shahadatain), establishing prayer, giving zakat, fasting Ramadan, and performing Hajj to the Sacred House. An individual enters this religion by uttering the two testimonies and then commits to the rest.