Hi Kibuchi,
The models can only run in a running dashboard. In the project overview page, in the upper right corner of the screen, there is a box that says 'Running'. If the number next to it is 0, there are no dashboards running. If the button is green and the number is positive, you can click on the box to get to a list of your project's dashboards.
Any of the dashboards that have a 'stop' button available are currently running. Click on the name of a running dashboard to connect to it, view the output of R, and enter more input if needed.
Cheers,
Anand