Which Christian denomination is the right one? How can you tell?
Jesus told Peter he would build his church (Matthew 16:18). The word "church" is singular; Jesus built only one church. Unfortunately, even in the early days of the church, men could not leave the perfection created by God alone. They started making changes and those changes become the root of divisions. "Now I plead with you, brethren, by the name of our Lord Jesus Christ, that you all speak the same thing, and that there be no divisions among you, but that you be perfectly joined together in the same mind and in the same judgment. For it has been declared to me concerning you, my brethren, by those of Chloe's household, that there are contentions among you. Now I say this, that each of you says, "I am of Paul," or "I am of Apollos," or "I am of Cephas," or "I am of Christ." Is Christ divided? Was Paul crucified for you? Or were you baptized in the name of Paul?" (I Corinthians 1:10-13). Isn't it sad that people now glory in their differences, thinking that they are pleasing God by doing as they please? "For do I now persuade men, or God? Or do I seek to please men? For if I still pleased men, I would not be a bondservant of Christ" (Galatians 1:10).
The only true church is the one founded by Jesus Christ. The only way to find it is to learn about its teachings from the book that defines what is the church -- the Bible. Man-made creeds and statements of faith are not going to lead you to the true church.
Of course, this means work on your part. You are going to have to become familiar with what the Bible teaches so that you are able to discern whether a particular church is following after the truth or after man. "For though by this time you ought to be teachers, you need someone to teach you again the first principles of the oracles of God; and you have come to need milk and not solid food. For everyone who partakes only of milk is unskilled in the word of righteousness, for he is a babe. But solid food belongs to those who are of full age, that is, those who by reason of use have their senses exercised to discern both good and evil" (Hebrews 5:12-14). Using the word of God, you need to put groups to the test to see if they are following God's teachings. "Beloved, do not believe every spirit, but test the spirits, whether they are of God; because many false prophets have gone out into the world" (I John 4:1).