The Bible clearly teaches that there’s only one God in Deuteronomy 6:4, Isaiah 43:10, Isaiah 44:6&8, John 17:3, and more. There’s the “oneness” part of the Trinity.
The baptism of Jesus in Matthew 3 is a great example that distinguishes the Father, the Holy Spirit, and Jesus. Clearly, they are distinct persons.
To demonstrate that each one of these persons is divine, we would look at the deity of Christ and passages like John 1:1 or John 10:30 where Jesus says that the Father and I are one. Acts chapter 5 writes that lying to the Holy Spirit is equated with lying to God. You have one God, and those three distinct persons are divine.