To place a Fibonacci retracement on a chart, choose the seashell icon:
You will then be able to click on your first anchor point, drag the mouse, and then click on the second anchor point. The retracements will be drawn, and a reference line will connect the two anchors.
If you mouseover any of the lines, it will give you details on the two anchor points as well as the value (both in percentage and price terms) of the chosen line.
You can also change many elements of the presentation of the retracement, such as its color, opacity, whether or not the reference line is shown, and so forth.