More to render the concept of Trinity understandable to Muslims:
You believe that God has 99 attributes.
Some of these are characteristics of God, as God in loving. This is a very important character of God, more so to the Christians.
This is an “acting” attribute, denotes action. You say God Loves, but He can withdraw His love.
However, there are other attributes as part of the existence of God, very basic by which the concept of God does not exist if you deny them.
Like: God do exist, if you deny this then you are saying there is no God, and turned to be a Kafir.
God exist is not an acting attribute, it is a very basic attribute as an ingredient of God’s very existence.
You can not say that God can withdraw His existence because it is a basic attribute of His very existence. He is every where.
Another basic ingredient of the basic attributes of God is He being Alive, He is not a dead God or made of stone.
As a mater of fact, He is the source of all life, so if He is not alive how can He be the source of life?
Another basic attribute of the existence of God is He is Wise, Thinking, He is the creator of the Universe, so He is the greatest Mind in the Universe.
He is not mute, He relates to His creation, He says Be so things are Made, by His Word He creates.
You can not say God does not create, neither can you say God is mute, neither can you say God has no mind; if you say any of these then you deny the very existence of God.
So God has these very basic attributes which if you deny any of it you deny the very existence of God himself:
1. He exists
2. He is alive
3. He is Wise and Has the greatest Mind in the universe.
Christians give these attributes or basic characteristics of God the following definitions:
1. God that exist: God the Father
2. God that is alive, by His Spirit: God the Holy Spirit.
3. God the Greatest Mind: God the Son, The Word.
Three in one and one in three.
The Creed says, the first sentence: We believe in One God.
(The Creed is what Christians recite to confess their faith)