The Trinity is a complex belief, true. It is the logical end to the picture when we look at who the Father, Son, and Spirit are.
The Father is emphasized as God. The Son is referred to as God in some places. An example of one is John 1:18
No one has ever seen God. The only Son, God, who is at the Father's side, has revealed him.
Jesus is also a preexistent being, scripture has rich support for this. Jesus was there at the creation. Jesus is higher than the angels, so isn't one of those. God calls no angel His Son. Jesus is referred to as God in some places. He is the Holy One, who is God. Jesus is referred to as the Holy one. The Holy One is proclaimed God in OT hymns.
The Holy Spirit proceeded from the Father and shares in being with the Father as does the Son. What shares God's essence and being is God. God from God. Little is said of the Spirit. The Spirit speaks in Acts, this is a person.
II Corinthians 13:13
The grace of the Lord Jesus Christ and the love of God and the fellowship of the holy Spirit be with all of you.
What we see here are three distinct persons.