It may seem difficult to convert to Muslim, but the initial steps of the answer to how to become a Muslim are fairly simple. However, just saying the Shahada does not end your journey in fact, converting to Muslim is the beginning for a life long journey into a faith that can impact your entire life.
Saying the Shahada is your statement that you are turning away from your past sins and moving forward in a new direction. But before you make that statement, you want to prepare yourself for the journey in front of you. First you will want to learn as much as you can about Islam and the history and path that lies in front of your. Read the Quran which is the holy book of Muslims. You can start with a translation, but it is recommended that you study Arabic and learn the original language of the Quran so that you can learn from the Quran just as it was originally written so that you don't get your information through the filter of another person. You should also study the Hadith to better understand the teachings of Muhammad. Once you are ready, get some witnesses to hear you repeat the Shahada. After this, you need to clean your body as a sign that you have washed away your past sins and renounce those sins as you move forward.
Once you have completed the process of saying the Shahada and cleansing yourself, you will now need to embrace and actively follow the life of a Muslim striving to engage in the life and understanding of the Quran and teachings of Muhammad. This will involve fasting and meeting the needs of those less fortunate than yourself. Remember that you have chosen to embrace a life of service and love for those around you.
Now that you have learned how to convert to Muslim, you have the chance to choose for yourself if this is the right path for you to take with your life. Take time to study what it means to be a Muslim and research all of the details of this choice so that you are prepared to choose wisely for yourself today.