Flow does not start


I downloaded the flow "PWM Control LED" from the Node-Red page [https://flows.nodered.org/?term=gpio&num_pages=1 ] and imported:
But if I will start the flow with: "localhost:1880/ui" I get the message:
"Please add some UI nodes to your flow and redeploy."
and with F12:

You are using the ngTouch module. 
AngularJS Material already has mobile click, tap, and swipe support... 
ngTouch is not supported with AngularJS Material! app.min.js:148:303
Rendered successfully. app.min.js:532:12831
CSS for generated in 396ms app.min.js:532:12831
Less has finished. CSS generated in 396ms app.min.js:532:12831
Source-Map-Fehler: Error: request failed with status 404
Source-Map-Adresse: angular-chart.min.js.map

nodejs = 12.13.0
node-red = 1.0.2
Raspberry = Raspian buster

Kind Regards
Juergen B.

That flow has not got any dashboard nodes to display anything, so there is isn't anything to display. All it does is drive a gpio pin to various values by clicking the inject nodes.

thank you for your answer.
Now I see clearly.
I did not know that with the "dashboard node".

Kind Regards
Juergen B.