Elements are listed vertically. Each element has its own timeline. You can select one timeline at a time, this way you don't get distracted by other open timelines and keyframes. Focus on one element and move on to another.
Click on the label (on the left) to select the timeline. Only timelines with properties can be expanded. If you don't have any properties on the timeline yet (for example when you start your first animation), make sure to add a property first.
Click on the
+ icon to add a property. A context menu will appear with the most commonly used properties. You can always change the property later on by simply clicking on the property name.
Right click on the property to remove it. This will remove the complete timeline and cannot be undone.
Add Element + button (on the top next to the time indicator) to add another HTML/SVG element to your group. As you can see, you can easily see how elements are nested in the active document.
You can not sort elements at the moment. This feature is added on the roadmap.
Right click on the label of an element to remove it. This will remove all properties and timelines and cannot be undone.