Getting Started notebook should mention edit/run mode, load times, code vs output distinction

[jangler]

The Getting Started notebook instructions for editing code don't mention the necessity of entering edit/run mode, which is not too difficult to figure out, but still confusing as a new user. I might have figured this out more quickly if the code and output for the first cell weren't identical, which confused me as to which is which.

It also takes the notebook ~30 seconds to become responsive on my machine. As a web app user, I typically expect load times up to a few seconds long, and start to wonder if something is wrong if loading takes longer, unless I'm expecting heavy computation. It might be good to mention the long load times here in some way.

As a side note, it's also odd to me that some of the plain text elements in the notebook (but not others) seemed to be blocked by computation, meaning that I can't read ahead reliably either while I'm waiting for content to load. I understand now that those text nodes are hidden cells.

Pluto.Getting.Started.issues.mp4