Could someone please explain volume on tradingview to me or provide me with some references

I used to think the volume represented how much had been trading within a given candle but am confused by the numbers presented. Why do the numbers in line 2 and 3 change when I change the number in line 1. I understand the explanation could be long but if someone could either explain briefly or provide a video or documents to read for me to understand that would be greatly appreciated.

When you change the number of moving average periods (which you have labeled â€ś1â€ť), I think you will find that the number you have labeled â€ś3â€ť will change, but the number you have labeled â€ś2â€ť will not change, unless you have moved the cross-hair (your cursor) to a different price bar.

Some additional info â€”

The colors of the volume histogram bars match the colors of the corresponding price bars.

Next time you post a chart, it would be helpful to include the labels indicating the instrument (in this case Bitcoin) and the time-frame.