battery and wireing info please

Thank you Roy - I have been researching what would be the right batteries for what I'm wanting to do which is how I found this web site. I have decided on a pair of 6v 220 golf cart batteries with a 45 watt harbor freight solar kit to start with and it seems like expanding the kit as needed would be a great place to start. I have done countless hours of research on youtube lol I was helped greatly by the forums I read on this site to come to my decision on the 6v220 batteries. Then once I decided I started investigating how to hook them up and saw the how to do that. Then I started checking the wires on the trailer and it appears that maybe the 2 small gauge black wires will connect to the white battery cable and positive has a small gauge black wire connected to it already but the end of that feeds into a small plastic connection fitting of some sort and a red positive on the other side of that needs a small gauge black wire would go there also but need confirmation