Electrons are a negatively charged fundamental particle that forms part of an Atom. The Proton or protons in the nucleus of an atom have positive charge, the two charges exactly cancel out leaving the atom neutral. A proton has a mass that’s 1,840 times larger than an electron.
If you can’t understand this section, you should either read up on quantum mechanics of go back to reading whatever interests you. Electrons are standing waves that fade off with increasing distance from the nucleus. Electrons are waves as well as particles because of quantum mechanics. In fact, everything is both particle and wave, though on macroscopic scales, we see only particlelike or wavelike aspects.