The Classes tab of the course Analytics page provides aggregated student participation and engagement data for each class in the course. There is a bar-graph at the top for "at a glance" perspective on each class, and a more detailed grid-view of the data at the bottom.
Each bar in the graph is a class, and each row in the grid is a class. Data is only shown for classes that have already happened or those with no date/time. As classes occur (their date/time passes), they are added to the data on the page (both as bars in the graph and rows in the grid).
This data is updated once daily, at 00:00 (midnight) UTC (UTC is also referred to as Greenwich Mean Time or Zulu Time). Depending on where in the world you are, your data may change during the day or may not change until overnight. Just understand that you will not be able to see student interaction data until the data updates occur (so not immediately upon occurrence).
You can SORT the data in the grid by clicking any of the column headers, or you can export the Class data shown (along with other fields) for reviewing in detail offline. See Definitions of Analytics Data Metrics for detailed definitions for each of the data fields/metrics.
Hover your cursor over a bar in the graph to get a quick-view pop-up of the participation data for that class, as shown in the below figure.
Analytics for LIVE classes - The Viewing data for Live-streamed classes is a little different than for VOD (recorded then posted) classes. For Live-Streamed classes, students viewing the live stream probably have 100% for attendance, as they must be in the classroom to view the stream at the time it is happening. However they do not get credit for a "video view" because the live stream is not a "video" until it is processed. If the student views the capture of the class again later, then they will get credit for a video view. Notes counts are tracked for live classes, as are questions and responses, and any polling question responses if there are any posted to the live class to accompany the feed.