These keywords interact with internal data structures, known as objects, and with the computer itself. The name object-orientated may throw you a bit. To understand it, stop what you are doing for a while and take a look around at reality. Each of these objects can be further divided, there are tall people, short people, red cars, blue cars, PCs and Macs, and so on. Each of these objects does things.
People talk or walk, cars go forwards or backwards, birds fly, etc.
So, logically, when we try to model reality on a computer, we create objects. OOPLs also involve events. An event is something that happens, so for example, a bird could land on a branch or a haircut could change. The most basic computer programming term is a variable. A variable can hold whatever we want it to.