The timeline is the section of the module editor [?]
The "Module Editor", also known as the "Visual Editor", is an interface used to create & modify modules.
It's through this interface you can add various types of layers to your modules, as well as animation and special FX. dedicated to animation and controlling the stacking order of layers [?] Layers are containers for visual, audio or layout items and are added to slides. For example, text, button, image, audio, video, group and row are all types of layers.
Layers are added to slides via the module editor..
From this part of the editor animations can be added, adjusted and previewed. Additionally, layers can be selected from the timeline, and can be dragged and dropped up and down on the timeline to modify which appear in front and which behind.
It can be equally compared to both a timeline in a typical video editing application, and a layers panel in a typical graphic design application