Once you believe that Islam and the Quran are the truth and Prophet Mohammed (pbuh) is the last messenger of GOD, the only step is to declare that belief by stating, “I bear witness that there is none worthy of worship except ALLAH and that Muhammad is ALLAH’s slave and (final) messenger.” This is called the “Declaration / Testification of Faith (shahadaa)” and is the first pillar of Islam. It is better to inform some Muslims (frind) of this even if you are keeping it as a secret. Simply declaring belief in Islam, the Quran, everything that the Prophet Muhammed (pbuh) taught.