One approach would be to look for application notes on relevant topics or similar applications. Analog/Linear’s AN-118 might be one example focusing on discrete/self-oscillating topologies. As with most design problems there’s more than one road to the same destination, and much depends on where you’re starting and what sites you’d like to see along the way.
Though not as immediately relevant, Wurth’s trilogy of magnetics is a resource I’ve found worthwhile. A bit chewy, but lots of good information relevant to specification, selection, and design of magnetic components for a variety of applications.
For what it’s worth, I’ve found the signal-to-noise ratio and ease of finding good information to have diminished severely over the past decade or so. The price of publication falling essentially to zero has led to a lot of half-baked “content” being generated for the sake of generating something, and because a lot of the better content is older, it tends to get buried. Better info tends to be published in PDF format by component manufacturers as application notes; they’ve got an incentive to educate people on component selection and usage more so than to sell ad space.