Alright kiddo, so a surname is like a family name that people have. Much like how you have a first name, like "Emma," some people also have a last name or surname, like "Chal."
Now, Chal is actually a surname that comes from India. It is a name that is typically used by people who belong to a certain caste or group. A caste is like a social group of people who share certain characteristics or occupations.
So when someone has the surname Chal, it means that they either belong to this caste or perhaps their ancestors did.
Does that make sense, little one?