The rest you learn along the way.
As for the eInk laptop, I have that eDream as well. The hack I wanted was to use an LCD panel across the top for live editing, undo, etc. And then once the line was done, the eink display would wake-up, take the new line of text and write it to the display and then go back to sleep.
A couple nice eink options for the discriminating hacker
Well, don't leave us hanging, do recommend a book to start with
https://hackaday.com/2017/01/18/forrest-mims-radio-shack-and...
My recommendation for a current book, that is affordable is
"Practical Electronics for Inventors" by Paul Scherz
I think learning what common design practices like bypass caps, knowing when to apply certain formulas and when not (ohm's law / linear/non-linear components), and knowing where to find help when needed, especially for circuit review, was crucial.
Download kicad and watch a few videos and most software devs I know would figure out enough in a short amount of time.
Bonus points if you understand constraint systems because that's pretty much the entirety of CAD.