While we recommend looking up what climbing is and how to get into it, we’ll do our best to bequeath a bit of wisdom unto you:
Climbing/bouldering is pretty much about trying to climb to the top of a mountain or boulder with your hands and/or feet.
Usually you climb on what's called a route (think of it as a hiking trail).
Climbing can be a sport, hobby, workout, pastime, meditation, or whatever you want it to be.