A relatively newcomer to Premier Pro and still finding my way around it.
Would someone please explain to me what the three headings at the top right of the main interface are meant to do? The headings would seem to make it obvious but I seem to be able to do everything from the Learning persona. What are the advantages/disadvantages of using those specific personas (assembly and editing)?
On the Learning workspace, you are shown training lessons that you can familiarize yourself with to understand the installation.
Assembly is a page for downloading, organizing and preparing your material for installation. Here you can also perform rough editing, that is, select frames to create a story.
Editing - allows you to perform all the possibilities for creating videos, working with effects, animation, graphics, text.
This is the main area for creating your masterpiece. The PrPro program allows you to customize workspaces at your discretion by mixing parts of the specified areas together for ease of use, saving time.
I just wanted to emphasize Baffy's comment, especially the last part. One of the perks of Premiere is having a very modular workspace. You can customize it however you want and save that as a workspace preset. I think some newcomers think they need to be constantly changing workspaces all the time to get access to different windows/panels or to change what they're doing, but those are all just different arrangements of the UI. Some people may like changing the workspace all the time. Personally, I prefer havng my own workspace that covers me for about 90% of what I ever need to do. The only alternative workspace I switch to is when I do color grading. So just understand (OP) that those are just UI configurations, but you can build it however you want and make it your own. All windows/panels can be opened from the Window menu at the top.