But in very vague terms, you will do it exactly like you'd learn to code:
- start reading why/how electricity works[1];
- start making basic circuits with light bulbs or small motors (light bulbs NOT leds) with various switches and try to understand how/why is (not) working;
- start reading to see what basic components are doing: resistors, transistors, diodes, capacitors, transformators/coils; what they do, why they do.
- start combining basic components with the above light bulb. See what happens if you add a resistor or a diode, what a capacitor do and stuff like that.
Jumping from the very begining to arduino boat will only leads to major frustration overtime.
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[1] http://www.instructables.com/id/Electronics-for-Absolute-Beg...
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If you want to also practice, make this as step 1:
- get a soldering iron and some old boards (from an old TV, old radio, stuff that are not build only by integrated circuits) and start exercising (de)sorldering.
"Lessons in Electric Circuits" by Tony R. Kuphaldt is a pretty good introduction to the basics, you can find an improved version online: http://www.allaboutcircuits.com/textbook/
The most popular book is probably "The Art of Electronics", it's pricey but well worth it if you're serious: https://www.amazon.com/Art-Electronics-Paul-Horowitz/dp/0521...
Check the usual suspects for communities, e.g. Reddit (/r/electronics, /r/AskElectronics) and StackExchange.