I want to build a robot for the science fair. i do.t know anything about them and need explanition?

I would like to build a remote control robot with a pneumatic arm like a battlebot I have 400 bucks to spend probably maybe a little more. I’m handy with building but just need to know stuff from the beginning. Websites I have found assume I know stuff about controllers and motors and all that fancy talk. Please help I am clueless!

If I were you, I would choose a simpler project, and one that uses the scientific method to test a hypothesis, i.e. an experiment. In science fairs that I have been involved with as a judge, one is scored more points for an experiment than for a demonstration which is probably how judges would classify construction of a robot. Experiments can be very simple, such as one that I judged that experimented with the effects of caffeine on meal worms. This project won the gold star because the student set up the investigation as a rigorous experiment with a control group of meal worms that were fed no caffeine, and other meal worm groups that were fed different amounts of caffeine in their diet. But the sky is the limit on what physical or biological phenomenon you wish to investigate.