The Job Page
The Job page is accessed from the navbar. On that page you can monitor the running state of all the notebooks you have access to.
The colored indicators on the notebooks tell you the running state of the individual paragraphs contained within that notebook. Next to the name of the notebook is the main interpreter used in it.
On the right edge you can see the status of the notebook and the option to run the notebook (see more about statuses here). While a notebook is running you can also abort the job.
You can search for the notebook you want by using the search bar and sort the list by modification date. You can also filter the notebooks based on their main interpreter.