I explain it with a comparison.
We humans are a trinity too. We humans consist of a body, a soul and a spirit. And yet we are not 3 humans but only one human. It is the same with God, he consists of a body, a soul and a spirit. And yet it is not three Gods but only one God. The body of God is Jesus, the soul of God is the Father and the Spirit of God is the Holy Spirit. But the difference between us and God is that he can share himself and we can not. Now you ask yourself what Jesus was before he became human (body). The answer is, he did not exist and did exist anyway. Jesus as a person did not exist but he was always there. It's like the humans. If somebody asks a human, how long do you exist? Then you have 2 answer possibilities. The first one is: since my birth. The second is: Since Adam and Eve. The first answer is related to the person himself, the second is related to the nature. All human beings are one nature, namely: human. So it is with God the Father and God the Son, they are one nature, namely: God. So, if you ask Jesus, how long do you exist? then he also has several answer possibilities, but there are 2 differences with Jesus, the first is, he has 3 answer possibilities, the second is, he consists of 2 beings, he is the son of a human and the son of God, he is human and God at the same time. So, if you ask him: How long do you exist? Then he have 3 possible answers, the first one is: Since my birth (as the person himself) the second is: Since Adam and Eve (as human), the third is: I have no beginning (as God).
Do you understand it?
We humans are a trinity too. We humans consist of a body, a soul and a spirit. And yet we are not 3 humans but only one human. It is the same with God, he consists of a body, a soul and a spirit. And yet it is not three Gods but only one God. The body of God is Jesus, the soul of God is the Father and the Spirit of God is the Holy Spirit. But the difference between us and God is that he can share himself and we can not. Now you ask yourself what Jesus was before he became human (body). The answer is, he did not exist and did exist anyway. Jesus as a person did not exist but he was always there. It's like the humans. If somebody asks a human, how long do you exist? Then you have 2 answer possibilities. The first one is: since my birth. The second is: Since Adam and Eve. The first answer is related to the person himself, the second is related to the nature. All human beings are one nature, namely: human. So it is with God the Father and God the Son, they are one nature, namely: God. So, if you ask Jesus, how long do you exist? then he also has several answer possibilities, but there are 2 differences with Jesus, the first is, he has 3 answer possibilities, the second is, he consists of 2 beings, he is the son of a human and the son of God, he is human and God at the same time. So, if you ask him: How long do you exist? Then he have 3 possible answers, the first one is: Since my birth (as the person himself) the second is: Since Adam and Eve (as human), the third is: I have no beginning (as God).
Do you understand it?