If you want to understand electricity, you first need to know a little about matter, atoms and electrons.
Matter is anything that takes up space or has mass. Everything you can touch is made of matter.
Atoms are the very smell "building blocks" of matter. Everything you touch is matter and is made up of atoms (lots and lots of atoms!). These very small atoms are made up of an even smaller nucleus and one or more small electrons circling the nucleus.
Electrons always have a negative ( - ) electric charge, and it is this electric charge that is responsible for what we call electricity.