iMovie updated (June 2019) and editing timeline is missing

Hi, iMovie updated a couple of days ago and it seems to have reverted back to its original state. By that I mean it doesn't come up the way it used to. The screen would usually have my projects in the top left, the video playing screen in the top right and the editing timeline at the bottom. Now there's no editing timeline and I can't find how to display it. I've gone to "window" and "revert to original layout" is grey and can't be selected. There doesn't appear to be any other obvious way to display the timeline. Does anyone know how I can resolve this?