How do you get started?

That depends on what you want to learn. I can give vague, general, broad, diffuse advice. But, the best thing to do is do one thing at a time. (I wish I could say that was my idea.)

From your posts I surmise you are very thorough, like to create structure, are very opinionated, and have little or no problem expressing yourself thru writing.

I recommend this path outlined below. Make it your own. It's obtuse and sparse for a simple reason.

On the matter of a beginning:
1. Pick up a cheap second-hand computer or get one donated to you.
(Get creative on how to do this. You'd be surprise, once you put it out there, how willing people are to give you old computers and other stuff once you say the words "I'll take it.")

2. Totally muck up that computer.
Learn how to install new hardware and new software. Commit to a high level of discovering new applications each week. (I find, on average, a new piece of hardware or software program for an existing problem/research request about once a week.)

3. Blog your exploits.
Make yourself accountable to other people. The biggest way to push yourself to develop any skill is by surrounding yourself with people who are better at something than you are. That and 10,000 hours.