Start from conservation laws, get a feel for the typical mechanics problems. Acceleration, forces, work, energy, momentum. (At first don't try to understand WTF

Start from conservation laws, get a feel for the typical mechanics problems. Acceleration, forces, work, energy, momentum. (At first don't try to understand WTF all that has to do with symmetries/invariants.) Then a bit of EM. (Circuit analysis, RLC circuits.) Eventually you'll need some undergrad level math. To get a few very concrete (hehe) examples maybe look into a bit of structural dynamics (resonant frequency, tuned mass damper, mass distribution described by a matrix). Then eventually you need to be able to solve simple differential equations and know what Fourier has to do with radios, and how mechanics depends on calculus of variations. The more examples you work through the more you'll know what you want to learn about. My recommendation is don't try to deep dive into one topic, instead start to look for similarities in other topics, basically do a breadth-first search.