Okay kiddo, let me try to explain a stabilizer subgroup to you in a way you can understand.
Imagine you have a group of friends who love to play hide and seek. Let's say one of your friends wants to be the seeker, and the rest of you hide. When the seeker finds someone, they tag them and that person becomes the new seeker.
Now, imagine that you and your friends like to play this game in a really big park with lots of different areas to hide. Some of you might like to hide in the trees, while others might prefer to hide behind bushes or benches. This means that the seeker might have a hard time finding everyone.
In this game, the stabilizer subgroup is like a special group of friends who always hide in the same area. Let's say your friend Sarah always hides behind the same giant rock in the park. She's part of the "rock stabilizer subgroup." This means that no matter who the seeker is, they'll always find Sarah behind that rock.
So the stabilizer subgroup is really just a group of friends who always stay in the same place or follow some kind of pattern. In math, this concept is used to help solve problems related to symmetry and group actions. But for now, just remember that the stabilizer subgroup is like your friend Sarah who always hides in the same spot in your game of hide and seek.