To do so, from the Webapps screen,
- click on "New Webapp > Code Webapp > Standard > Simple web app to get started"
- chose a name
- create the webapp
Other steps will be required. But they are documented in the webapp directly: for example you can in this case to go to the webapp settings and allow to read data from the dataset you want to read from.
I hope this helps.
Mickaël | R&D at Dataiku