Workspace
You should be familiar with the names of the window elements:

The most important elements are the sprite editor, the timeline, the color bar, and the preview window. Other familiar elements are the menu bar and the tool bar.
The timeline is not visible by default, you can make it visible from View > Timeline menu option or pressing Tab key. (Also it popups automatically when you add a new frame or a new layer.)
Drag and drop tabs
You can drag-and-drop tabs to a side or duplicate them using Ctrl or Alt keys:
SEE ALSO
Color Bar | Context Bar | Sprite Editor | Status Bar | Tabs | Timeline | Tool Bar | Menu Bar