As highlighted in the screenshot below the Up and Down arrows allow you to move the chart up and down relative to the other charts. Note if the chart is at the top, the up arrow doesn’t render, and likewise, if the chart is at the bottom, the down arrow will not render. Also note the top price chart can not be moved down, it always stays at the top.
The line icon highlighted below allows you to minimize the chart without closing it.
You can see in the screenshot below the Average True Range chart is minimized and is between the Football Field chart and the Stochastic Oscillator chart. To get the Average True Range chart back, you would click on the overlapping window, as highlighted below.
The window icon highlighted below allows you to maximize the chart so it is the only chart being displayed.
You can see in the screenshot below the Football field is now maximized. To return the chart back to its normal size, click on the overlapping window, as highlighted below.