You also need to have a Cloud Node-RED server that subscribes to your real-time data streams. If you don't have one, learn how to spin up a secure Cloud Node-RED server, and subscribe to data streams.
Navigate to the Node-RED of your cloud server. From the top right menu, click on Manage palette and select the Install tab.
In the search bar, search for dashboard and install the node-red-dashboard.
From the dashboard nodes on the left palette, drag and drop a gauge node and connect the desired data stream to it.
Double click on the gauge node to configure the settings and select or define a Tab and Group for this gauge on the dashboard.
From the top right arrow menu pick Dashboard, and click on the dashboard link icon to navigate to the dashboard url.
This dashboard webpage will be in the following format and publicly available over the internet. Since the dashboard is responsive, it will get resized properly for smaller screens such as your smartphone.