Okay, imagine going to school but instead of a typical classroom, you go to a special school called a yeshiva. At yeshiva, you learn all about the Jewish religion and study Jewish text, such as Torah and Talmud. Your teachers are called rabbis who are very knowledgeable about Judaism and they help you to understand and explain the meaning behind the text.
Just like in regular school, you have classes and homework but in yeshiva, you also participate in prayer and other religious activities. Some yeshivas allow students to live on campus, so it's like a boarding school. And just like regular school, yeshivas have different levels from elementary to high school and even to college.
Overall, yeshiva is a special school where Jewish children learn all about their religion and how to live according to the Jewish faith.