Direct from the ’80s: the most comprehensive video explainer on synthesis for beginners.
Don’t let the aesthetics fool you: this is a fantastic three-hour presentation from Dean Friedman at the N.Y. School of Synthesis from, presumably, the early 1980s. Split into three one-hour sections, each video takes you step-by-step from zero to synthesis hero (via matrixsynth).
Ready for more?
Intro to Modular Synthesis looks at combining different devices, or modules, to create all kinds of sounds:
… or a Quick Recap of the Basics?
Shorter-form, easy-to-follow resources on synthesis for beginners: