Open an active flow from the Flows list and click on a step to view statistics, including detailed information about how contacts have acted and how many contacts have passed that step.

Note that for snooze steps, the sum of Contacts here right now and Contacts passed this step may exceed the total number of contacts in the segment, because snooze statistics are calculated from all of the contacts who have ever passed this step. Remember that segments are updated dynamically, so some of the contacts who passed this step may no longer be in that segment.