The simplest robot is a toy car with wheels that can move on its own. More complicated robots can be controlled. Some robots are remote controlled by cables or radio waves and others have built in computer programs to do the controlling from some sort of software program. Remote controlled model aircraft can be considered robots. The robot may have wheels or arms, or hands or many other very odd configurations.
Good robots can do useful work.
They can work in hazardous conditions where humans would not want to be. Robots can take on many different configurations. Well, there are thousands of ideas already out there and hundreds of levels from the simplest non controlled robots to sophisticated space robots. In a kit the idea of a robot has been made for you. What it can do and how it does it has already been decided and designed.