I don't know where to look for the history of the baptism of John. I have the understanding that baptism was done since the Babylonian captivity for the conversion to the Jewish faith (a proselyte, but I don't know where to find any documentation to confirm or deny it. I just don't know where to find it. I only get general and vague answers to my question as they don't seem to take the question seriously.
I have found a reference to it in Barne's Notes, but I don't seem to find much more on it. I am using PC Study Bible V5 and have not much experience with the program to fully find what I am looking for. I did find an article in the International Standard Bible Encyclopedia. It seems to be the answer I am looking for, but I am not sure since it doesn't really say when it started.
What else should I be looking at? What more should I know on the subject?
The reason you are having trouble is that you are looking for something that isn't there. It is provable that the Jews did not practice baptism from the challenge the Jews directed at John.
"Now this is the testimony of John, when the Jews sent priests and Levites from Jerusalem to ask him, "Who are you?" He confessed, and did not deny, but confessed, "I am not the Christ." And they asked him, "What then? Are you Elijah?" He said, "I am not." "Are you the Prophet?" And he answered, "No." Then they said to him, "Who are you, that we may give an answer to those who sent us? What do you say about yourself?" He said: "I am 'The voice of one crying in the wilderness: "Make straight the way of the LORD,"' as the prophet Isaiah said." Now those who were sent were from the Pharisees. And they asked him, saying, "Why then do you baptize if you are not the Christ, nor Elijah, nor the Prophet?" (John 1:19-25).
This is the first mention of baptism in the Bible. Water was used in the Old Testament for ceremonial cleansing to remove uncleanness (Numbers 19:7), but there is no mention of complete immersion, particularly in connection with the removal of sin. That it was a new rite is shown by the Jews' question of John, "Why then do you baptize if you are not the Christ, nor Elijah, nor the Prophet?" (John 1:25). They questioned his right to add a new ordinance if he did not have sufficient authority.
The current fad is to believe that Christianity slowly evolved from prior beliefs and practices; thus, people search for evidence of ideas being developed by men over the ages. The fact that God is determining what is being done and He changes things according to His purposes doesn't enter into their minds.