What is plastic explain it to me?

what is plastic? it is what we use in our everyday lives and is molded and shaped and melted down and re-shaped but what is this substance where does it come from how is it generated and made. i tried researching it but the way it is broken down is like AP chemistry and i dont understand it so can someone breakdown what plastic is for me im just curiouse AP chemistry and i dont understand it so can someone breakdown what plastic is for me im just curious