Where in the Bible does it explain about the Holy ...

I don't believe the word is in the Bible. But God does talk about the Trinity. The Trinity is one God existing in three persons. This is a very complex and perplexing issue to understand. I myself don't quite understand it in full. But when I say three person I don't mean three Gods. There's only one God Deuteronomy 6:4.  In Genesis 1:1,26, Matt 3:16-17, Matt 28:19 it talks about the Trinity being three persons. Each person is God read John 6:27, Romans 1:7, 1 Peter 1:2 this is about God the Father. Than about God the Son read John1:1,14, Romans 9:5, Hebrews 1:8, 1 John 5:20. Now you have God the Holy Spirit read Acts 5:3-4 and 1 Corinthians 3:6. I am sure there are more scripture about the Holy Trinity but this is all I know like I said before it is complex and perplexed. Hope it helps you. Good Luck.     

Let you read for yorself , but no once will you find the word "trinity" ocurring in the inspired Bible. One of the outstanding features of the pagan religions was its triads of gods and demons. In the latter half of the second century religious writers who claimed to be Christians began to introduce the word into their writings . Came the fourth century and the rise of Constantine the Great. After he took an interest in tne Christianity  of his time, Constantine became aware  of the great controversies that were rending it, particularly that over the relantionship oF God to his Son Jesus Christ and to the holy spirit. This religious disunity threatened the unity of his empire. Hence in 325,as sole emperor and as Pontifex Maximus , he called together a religious council for settling the controversy over the "trinity".  

This question has a very easy answer, yet most over think it, I know I did. There is no such thing as “the trinity” or “a trinity“ in the Bible, it cannot be explained without man made all over the place thought, for it does not exist. However it has definitely been expounded on through many religions.
It may be encouraged as a reference for: Father, Son, and Holy Ghost, or Spirit, Soul, and Body, but the bottom line in my opinion is that the Bible is revealing the Threefold Nature of God, and mans Trinity (three) of Being with God, and the trinity of itself when being referred to in the Bible is only conjecture.