“trinity” is a made up word, meaning “three in one”. There is nothing wrong with the word, though some people object to it. We use the word to describe the mystery that God has revealed of Himself. If humans “made up” God, don’t you think humans would have made up a God Who was easier to explain?
Look at your water example.
The substance is physical—H2O. one molecule of H20 is always the substance called H20. But that molecule of water manifests itself as ice, water, and steam.
Pretend that that molecule of H20 has a mouth and can speak.
It would say, “I Am H20, I Am ice. I am H20, I Am water. I Am H20, I Am steam.”
Now look at the “spiritual substance” that is Almighty God.
He does have a mouth, and He can speak, and He says, “I Am Almighty God, I Am Father. I Am Almighty God, I am Son, I Am Almighty God, I Am Spirit,
Because they are three, they can move separately when needed.
The Son came to Earth in a man’s body, while the Father stayed in heaven. The Spirit came to be with us while the Son is in heaven.
Yet they work together. The Father spoke, let there be light, and the Hand of the Son made the light, and the light came into being by the power of the Spirit.
In this world of TIME, ice, water and steam must manifest themselves one at a time. Wrap your mind around a piece of Eternity, where ice, water, and steam, can manifest themselves simultaneously. God lives in Eternity, and is above and outside of Time, and is able to do that, even if your mind can’t wrap around it.
The Word has always been. The Word is with God. The Word is God.
Time itself is a trinity. Past, Present, Future. Yet you cannot touch Time without touching “Present”. Tomorrow what used to be Future becomes Present, and can now be touched.
You cannot touch God without touching the Son.
a person can go on and on explaining this concept, but you will never be able to wrap your mind around it in this life, because in this life your mind is to small.
So just rejoice in His revelation of Himself. Don’t worry about it or try to explain it with your carnal understanding. Let the Spirit teach you, as you walk day to day with Him, how He manisfests Himself separately as Father, as Son, and Spirit, and also all together as Almighty God.
Every time you think you have explained it to yourself, He will get “bigger”, and you will realize that your human understanding and human words just aren’t big enough to explain it. Just keep praising Him. He’ll help you undersand a little at a time.