For me, it was mostly podcasts on commutes and physical chores. I listened to podcasts about web development, JavaScript, backend, data flows, infrastructure. I built small systems that used this understanding, cementing it in my brain with the pros and cons of approaches where the rubber meets the road. Then I listened to podcasts about small business, particular successful SaaS companies, marketing, sales approaches, management, hiring and all the ingredients that made them successful. Side benefit of this exploratory research is that it makes you very valuable in the market.
Find a need, think of how to serve that need, judge its longevity, quality, and value. Then you put your now sharp tools to work. Idea evaluation is a good skill, and required. You need to be brutally rational about the ideas. Emotional attachment helps drive your motivation to work on it, but it won't magically make customers appear.
Then you try to execute. Good execution is the hardest part, and you give yourself the best shot by head down improvements in your skills. For software, your first goal is to produce something that serves the need and can acquire a few paying customers. The less "other stuff" involved the better, just serve the need. Once you have paying customers leverage their feedback to grow the product and pick the best direction to feel out where the market for it really is. Non-paying feedback is much worse than someone else with skin in the game, paying customers are key.
It's a lot more blood and sweat than the article seems to point out. I like bootstrapping, but it means long evenings and weekends unless you have a sizable nest egg for a runway. Or better if you can afford to work only part-time and can find an accommodating position.
Be ready to fail the first few times and try again. 2-3 significant failures under your belt is pretty normal for a successful SaaS bootstrapper.
If you have the stomach and drive for it. Then you to can reach this definition of success.
There are tons of small underserved markets that would provide nicely for an individual or small team.