It teaches you step by step all the aspects of a synth engine: oscillators, wave shapes, amplitude, filters, modulation, unison, FM… But most of all it trains your ear, which allows you to replicate the sound in your head and build it from scratch.
If you're a late beginner/early intermediate player and trying to move past the chord shapes and scale patterns rut, I strongly recommend William Leavitt's A Modern Method for Guitar. It's hard - really damned hard - but it's logical, the difficulty curve is fairly linear once you get past the shock of traditional notation, it inculcates good habits from the outset and it provides you with a very broad base of technique that is applicable to all styles of guitar.
https://www.amazon.com/Modern-Method-Guitar-Volumes-Complete...
Oh man, I missed this app when I switched from Android to iOS. So glad it's finally on iOS!
Once you've got that down, most popular synthesizers use a very similar "subtractive" architecture, so once you understand the basics of your chosen one, it's simple to follow tutorials using other synthesizers. From there I'd recommend finding a youtuber you like learning from even if they don't use the same synth as you.
https://www.soundonsound.com/search/articles/%22Synth%20Secr...