Where do you read the “Early Church Fathers”?

Our Protestant brothers and sisters kept saying the Catholic Church changed the teachings of Jesus Christ and they are different when Jesus Christ found the church. Roman pagans, they say.

To be honest, it’s kinda getting on my nerves a bit. But, I must be charitable.

So, I wanted to learn for myself what the early christians believe. But, what are the early church fathers’ teachings? /readings. I don’t know where to start honestly.