In the status bar of your Samsung Galaxy S8 you will see the notifications like new e-mails or WhatsApp messages. By default, the status bar is set so that from 3 notifications only a "..." is displayed in the bar.
Only by pulling down the status bar you can see all notifications. If you do not want this, but always display all notifications in the status bar, then you can change this setting as follows:
1. Start from the home screen and open the app menu
2. Select the settings and then "display"
3. Select the option "Status bar"
4. Now deactivate "Only newest notifications" by using the controller and the notifications are now fully displayed in the notification bar.