Okay kiddo, so a home demonstration club is a group of people (usually women) that come together to learn new things about running a household. They learn how to cook yummy meals, sew clothes, and even take care of the garden.
It's kind of like a class where everyone works together to learn new skills and share their own tips and tricks. They meet in someone's home and usually bring samples of what they have made to share with each other.
These clubs were really popular back in the olden days when women spent most of their time at home taking care of their families. It was a way for them to socialize with other women and also learn how to improve their home lives.
Even today, some people still belong to these clubs and they are a great way to learn new things and make new friends!