From the Overview tab, you can see the performance of your overall portfolio over time, so you can gauge if you are losing or gaining money.
If the $ amount and percentage are green, it means your portfolio is performing well. If the $ amount and percentage are red, it means your portfolio is performing poorly.
You can also see the performance of specific positions you hold within your portfolio. To do so, simply click on the stock for which you’d like to view the performance, which will open the overview page of the stock in question