The basic is actually rather simple.. A coil connecting the + and - of a battery, causing the coil to heat up. A wick, preferably cotton, to hold the liquid, and you get vapor to inhale.
If you can, check out some YouTube channels on mechanical mods and RDA devices. They are some of the simplest and most basic way of how the whole thing(
vaping) works.
The now many designs out there can be confusing, but look past the fancy external design factors and the basics remains the same.