Selecting a number (5, 10, 20, 50, etc) from the dropdown box will show that Moving Average on the chart. You can also type any number into the box, to show that Moving Average on the chart. Entering "0" will remove the moving average from the chart.

Clicking the "color box" to the left of the dropdown box allows you to change the color of that moving average.

Checking the "Bollinger Bands" check box shows the Bollinger Bands on the chart. Removing the Bollinger Bands will speed up chart viewing.