To use the features in the Historical tab, you must first get your free API key for downloading data at https://www.alphavantage.co/. Then you will save the key under Tools | Options > Stock Data as described here.

After entering the API key, you may select stock from the dropdown box, then select a time period and click Analyze. By the way, if you see <no stock information> in the drop-down box, you should press the Update button.

In the Data tab, you will see a graph of the raw data.

In the Trends tab, you will a graph of Regression, Seasonal, and Raw Data Avg (Raw Data Average). All three calculations are based on checked boxes for Open, High, Low, and Close. Unchecking a box will remove it from the calculations.

You may select values from the smoothing dropdown box under the time period dropdown box. You will see slight adjustments to the Seasonal plot. You should select the value that visually smooths this plot the most.

By the way, do not use for financial planning or investing. People nor technology can predict the future.