The Trend widget displays Process Sum widget data on a normalized scale so users can see variance in trend lines.
In order to use the Trend widget you need to have created separate Process Sum Widgets, that are Group by date period - Reporting type for the data you want to display.
Once you have created your Process Sum Widgets navigate to the dashboard that you want to add the Trend Widget to and click Place a widget >> + Add a widget >> Process sum trends.
Add a Widget name and Display text.
Then add the Process Sum widgets to the Widget table by clicking + Add row and choosing the appropriate widgets.