First, go to the Template section in Instadeq by searching it and selecting it in the search box in the navigation bar or by opening the menu in the navigation bar.
A list of templates will be displayed each with a + button on the right side.
Select the + button on the right of Visualization from MQTT (IoT) Source, the message Imported should appear below it after some seconds.
Go to the Home section by selecting the home icon on the navigation bar.
In the Visualizations section there should be an entry titled MQTT: Broker Message Stats, select it to open it.
If the entry is not displayed in the first 3 entries use the search box below the entries on the bottom right or the pagination controls on the bottom left of the Visualizations section to locate it.
Explore the configuration, try modifying it to suit your needs.
This examples uses a public MQTT broker provided by the Eclipse foundation, you can read more in the Eclipse Getting Started Guide, Sandboxes Section