Scenes and Sequences can be accessed by two different view modes - view mode and edit mode. You can switch between these modes when you are viewing a scene or sequence. You can access the view switcher in the top right corner is a view mode button to toggle between views.
View mode is a way of previewing your content or current published state. It is the same view external guests have when you share an item with them.
If you're the owner of the scene or sequence or if you are a team member, scenes and sequences will always default to open in the edit mode. Edit mode is where you can modify scenes and sequences.
Note: Your access to the Edit Mode is dependent on your team permission settings.