Your Hirsch number is a special way to measure how famous a scientist is. It works by counting how many important research papers they have written, and how many other scientists have referenced those papers in their own work.
Let's say you are a scientist and you have written 5 papers. If none of these papers have been referenced by other scientists, then your Hirsch number is zero. But, if one of your papers has been referenced by 10 other scientists, then your Hirsch number is 1 (because you have one paper with at least 1 reference).
The more papers you write and the more references they get, the higher your Hirsch number will be. Some scientists have Hirsch numbers of 10, 20, or even 50! This means they are very famous in their field and their work has been influential to other scientists.
So, your Hirsch number is like a score that shows how important your work is to other scientists. The higher the score, the more famous you are!