If you have gone through the principles and message of islam. If someone has introduced you to these in the proper manner and context. If now you believe in the religion, its as simple as proclaiming your ‘belief in the one true god and his messenger’.
I suggest you approach the Fanar Islamic Center near souk waqif. They would be able to guide you in the best way and answer any questions you have. Feel free to contact me if you need assistance. May god bless you with the truth.