I can tell you how I did it:
Had my Dad start an electronics firm in my bedroom (other end of a finished attic - no walls) - learned a lot by helping out, studying & receiving a ham radio license & commercial radio license - later, designed & built stuff from the ground up - wire wrap prototypes, designing pc boards with black tape on mylar, building Heathkits - consulted a lot of part & device manuals (the TI TTL data books were fun)
My high school purchased a first generation DG Nova - still needed its bootstrap to be toggled in by hand. A couple of us spent long hours just fiddling with the thing. Hacking in BASIC. Other folks were building computers from kits (Altair, Imsai, Apple I).
Went to MIT, took a bunch of Electrical Engineering, Computer Science, and Cognitive Psych. I recommend Tannenbaum & Sussman for texts. Lab courses. A student job with Ray Kurzweil, working on speech synthesis.
Started a small time sharing company.
Went to work at a large defense company designing computers & systems, writing proposals.
Went to work at BBN - helped develop pieces of the early Internet.
Unfortunately a lot of those opportunities are no more. No more building Heathkits or kit computers, from logic chips to full systems (these days it's all on a couple of chips, and what was once a supercomputer comes pre-assembled in a smartphone). No more hobbyist clubs like the Homebrew society on the left coast, or the Boston Computer Society. And few people get to grow up inside a startup.
About the best available might be Ham Radio & FIRST Robotics. Where there are still opportunities to get hands on, under the hood, and develop stuff from basic components.
Also, makerspaces. Attach yourself to a team that's preparing for Burning Man - you'll learn about engineering.
There are some opportunities to build your own chips, once you know some basic electronics. From programming gate arrays, to designing larger chips, on a pc, then shipping the files off to a short-run foundry. There's lots of stuff on the web that provides details.