I'm going to assume you did your homework and studied what it is to be a Muslim. Being a Muslim is not an easy thing, it requires work, at the end of which is a huge reward. Let's go through a short checklist of "to do" items:
You made it through the short checklist and your faith and spirit is at an all time high, what next. This is where you perform the The First Pillar of Islam, the Shahadda or declaration of faith.
Ash-Hadu An La Illaha Ill-Allah, Wa Muhammadun Rasool-Ul-Allah
The transliterated text above simply means: I bare witness that there is not God worthy of worship except Allah, and that Muhammad is His messenger.