I don't know what I have to be a Christian
Why do you begin with "Google"? That is meaningless.
Read a chapter of Proverbs every day. Proverbs has 31 chapters so you can keep your place by just looking at a calendar. There is no religion or nothing in Proverbs and you don't have to believe anything. Just read to find wisdom. When you are comfortable with that, then read the bible from Romans to 2 Thessalonians over and over until you start to remember what it says. That is the part that applies to Christians.
The answer to your question is Romans 10:9 & 10 "That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved. 10 For with the heart man believeth unto righteousness; and with the mouth confession is made unto salvation."