It started because I was raised to believe, but like every healthy Christian I had to come to my own faith, and several things bolstered it:
The idea of the incredible complexity of creation appearing WITHOUT a creative and intelligent force behind it takes MORE faith than to believe in God.
The historicity, archaeological evidence, and consistency of the Bible in context, including the evidence for the actual resurrection of Jesus.
The impervious logic of Jesus' words coupled with His recorded actions.
The observance of minor miracles in the live of myself and others (too many "serendipitous coincidences" along with surprising healings).
Personal experience, spiritually, emotionally, and psychologically.
God used all of this to convince me if the Truth of His Word. I HOPE that He will do the same for you, my friend! 🫶🏻
The problem is, there are no short answers to the questions that you’re asking. Not any of that you’ll accept anyway. You’re also not going to receive the truth unless you’re open to it
I would encourage you to read "I don't have enough faith to be an atheist" by Frank Turek, "Reason for God" but Tim Keller, and any of the "The Case For (God, Christ, Creation)" by Lee Strobel. “Mere Christianity“ by CS Luis is an awesome Reed as well. At least two of the guys on this list started out atheists who began to search for whether God was real and true, and came to the conclusion that the evidence points to God and to Christ. Another very short book is “more than a carpenter” by Josh McDowell. Each of these presents multiple reasons to believe in, not just A god, but the God of the Bible.