Segments let users view a subset of all the data collected by Matomo. This could be something like URL of the page viewed, a date range, or any other combination of data that is being collected from Matomo. To create a new segment, log in and go to the Dashboard. Once there, click on button labeled "All Visits" (just below the red toolbar). This will pull up both pre-made segments and your personal segments. Segments will show realtime data right away, but historical data will need the archiving report done on it before that data will be viewable. That archiving report will be completed at midnight every day, so we typically recommend at least 24 hours for your segment to have all the data represented in it.
More details at: https://webanalytics.unl.edu