1. Click on hamburger icon.

2. Click on dashboard tab and open Funnel Chart in edit mode.

3. The Edit menu box appears as you click on Funnel chart icon. And a widget gets added in content place automatically in dashboard.

4. In Formatting Property click on Legend Property.

5. Enter Following details in Legend Background:
Background color: #6fe3fa
Background Opacity: 0.3

6. Fill above details in edit box, As Shown in figure.

7. Click on Preview and Save and Exit.

8. Now, match your Funnel chart with the below example, it should look like the figure below: