Pretty much basic stuff, which is cool. A lot about electricity is hinged on the conductance and resistance to the motion of electrons. every other thing is just an addition. I wrote a good post about this 7 months ago. might be a good read for you if you need to know more about resistance.
https://steemit.com/science/@pangoli/world-of-fun-and-resistors-all-things-resistance-and-cracking-a-resistor-s-colour-code-20171213t94653579z