Thanks. So it's quite apparent looking at the line as well what color the volume bars below it ought to be.
The size of the bar indicates the ammount of money being traded?
If there have been no trades then the trade price shows the last trade price, so it looks like a horizontal line?
I'm on my phone so not looking at the chart at the moment, but I believe the Y-axis on the left side is the scale for the volume bars. And yes, the higher the bar the higher the volume during that period.
No trades should be a flat price line.