In Canvas there's a couple of places you can look to examine student activity.

The People Area

Probably the easiest place to look, which is excellent for when a course is just starting and you want to check that students are able to get in ok, is using the People area of the course. Here you have a list of students, and you can easily see columns for Last Activity (last time they spend time in your course) and Total Activity (again in your course)

This image is a screenshot of the People area of a Canvas course. The image is cropped to hide any personal data but highlights two columns which provide useful data in tracking student engagement: Last Activity and Total Activity. The screenshot focuses on these with some sample data underneath showing dates of Last Activity, and number of hours, minutes and seconds for Total Activity

New Analytics tool

Secondly there's a dedicated tool called 'New Analytics' built into Canvas. Here's a guide that Gimblett the Centre for Innovation in Education has produced: https://www.liverpool.ac.uk/centre-for-innovation-in-education/resources/all-resources/introduction-to-new-analytics.html

Staff who have used this tool report back that they use it as a guide but not as a 'single point of truth': for whatever reason data does not get collected at all or on time, so it needs to be looked at alongside other markers for student activity. To this end, it seems common practice to build in checking points into your course design, things like quizzes that students are expected to undertake or other visible activities that take place as the semester proceeds, which allow you to plan in opportunities to evaluate student engagement and identify any cases which are cause for concern.