Hey, thanks everyone for the information and the links.
I REALLY was only wanting to know the ‘why’ about the color of the bars. This comment from a different thread by David Gadoury (thank you Jerry Beers) is what I was looking for:
“I like keeping things simple. When the price of the stock goes down, the volume for the day is in red. When the price of the stock goes up, the volume for the day is in blue. Of course, your colors can vary depending on variables.”
I appreciate all the other helpful deeper information, as well, but I already have a pretty good grasp on that.