How many divisions of Christianity are there, and which is the right one to go with?

To answer the first part of the question, some history might help. Jesus of Nazareth was Jewish; he lived and died as such, and during his ministry, he was very clear about who he was. “Do not think that I have come to abolish the Law of the Prophet; I have not come to abolish them but to fulfill them” (Matthew 5:17). In other words, he came to fulfill the prophecy (that God would send a savior) and deliver the message that the time had come to move on from the traditions, routines, and laws that focused on ritual and less on faith and forgiveness. It is important to keep in mind that during his life, he preached to people who were living in terrible poverty and under the brutal domination of Roman occupation, so this was a message that people were dying to hear.
When he died, his followers spread his message of hope throughout the Middle East; again, this was a message that people needed. People gathered where they could (mostly in small areas in their houses) and studied together. The letters of Paul in the New Testament are his reflections and advice to the people he encountered in various areas (Thessalonians, Galatians, Philippians, Corinthians, and Romans). The traditional Jewish beliefs began to clash with the “new religion” almost immediately, and followers of Christ branched off into another religion (Christianity), but because they were being persecuted, they went underground and remained fairly quiet. This persecution continued with the Romans until around the fourth century.
In 312 AD, Emperor Constantine the Great had a vision that God would lead him to military victory, and upon winning the Battle of the Milvian Bridge, he converted to Christianity. Constantine enacted the Edict of Milan, which allowed the worship of all religions: “we have also conceded to other religions the right of open and free observance of their worship for the sake of the peace of our times, that each one may have the free opportunity to worship as he pleases; this regulation is made so that we may not seem to detract from any dignity or any religion” (Constantine, Edict of Milan). Then, in 325, Constantine called a meeting of three hundred major leaders in Christianity to meet and unify their beliefs so that people would be clear about what Christ actually taught. Although the group did not agree on many points, the origins of the Bible were born at the Council of Nicaea; they decided which books and writings would be included as codified canon and which would not.
With Christians given the right to worship openly and a clarified set of beliefs, Christianity spread quickly. Catholicism is considered by many to be the first official church, but it split into two distinct factions, the Roman Catholic Church in the West and the Eastern Orthodox Church in Eastern European countries and Greece. Due to widespread corruption, people started to demand a reform in the Roman Catholic Church, and in 1517, Martin Luther kick-started the Protestant Reformation by nailing his Ninety-five Theses to the doors of All Saints’ Church in Wittenberg, Germany. So, another split (this time in the West) was created.
Over time, these divisions splintered into other factions, and today, there are many different variations on a theme. According to the World Christian Encyclopedia (Bar­rett, Kurian, and John­son; Oxford Uni­ver­sity Press), there are roughly 33,000 denominations of Christianity in over 238 countries. Groups can also be divided into larger cultural blocks as well as smaller traditional affiliations within a denomination. The varying branches make sense, since Christ’s teachings revolved around faith rather than ritual and tradition; people are able to take the basic beliefs of Christianity and tailor the traditions around what makes sense to them. That is not to say, though, that Christians are not unified in certain ideas. These core beliefs revolve around the teachings of Jesus Christ, set forth in the New Testament.
Which is the “right” denomination? That is a question for the individual to figure out. However, researching the history, the literature, the language, and the core beliefs and actions of the founder (Jesus and the disciples) and weighing them against specific denominations and/or churches and the people who run them might help.

There are many divisions of Christianity such as Baptist, Protestant, Episcopalian, Pentacostilism etc. , the choice in which one to choose is completely up to you by your own convictions. Please refer to James 1:26-27, which lets us know that only the pure religion is that which tends to the widows & orphans. Note that doesn't mean that just because a denomination as what is stated above decides to do as James 1:26-27 says is the "right one" to go with. No, it means the pure religion such as dealing with the core or heart of a religion "blessed are the pure in heart for they shall see God" 

Like with most religions, Christianity can be divided into a large number of divisions or denominations. There are five major groups of denominations that include the Church of the East, Oriental Orthodoxy, Eastern Orthodoxy, Roman Catholicism, and Protestantism—which itself is made up of smaller denominations such as Adventist, Baptist, Calvinist, Lutheran, and Methodist.
While Catholicism has the highest number of followers, each division of Christianity has its own practices and specific beliefs. Since Christianity is a religion that exists throughout the entire world, there are many different forms one can find it in, even amongst any specific division.
Each division of Christianity differs due to a long history of the religion; many contrasting and conflicting ideas have been discussed passionately, and many important religious figures have existed. While Methodism may identify with the evangelist priest John Wesley, Lutheranism identifies with the teachings of Martin Luther. Catholicism, on the other hand, principally operates under the belief that Catholicism itself is the only true church founded by Jesus Christ.
In terms of deciding which division is the right fit for an individual, there is no objective answer. When considering a religion or denomination to follow, it's important to weigh one's personal beliefs to find what they fit best. Talking to religious leaders to discuss the ideologies and practices of each religion/denomination is also helpful in gathering an understanding of which would be most appropriate.