Your instructions from website -- To best understand T2115, pull up the chart and plot a comparison graph using the Dow Jones Industrial Average (DJ-30).

Set the time frame to weekly

and remember to set your scaling to arithmetic when using the T2 indicators compared to a market index for a true picture of volatility

How is this done?  What are the steps necessary to accomplish this.

Thanks in advance 

Click on Price History (the symbol and possibly company name in green at the top of the pane where price is plotted) and choose Comparison Overlays from the list.

You will want to put in DJ-30 on one of the lines and then check it.

Comparing Price Plots Visually (4:13)

You can click on the A at the bottom of the price scale (where it says AL%F) to set the price scale to arithmetic.

Price Scaling (5:46)