Associative memory is like a big book where your brain keeps all the things it needs to remember. Imagine the book has lots of pages, and on each page there are different pictures or words that remind you of something specific.
For example, if you see a picture of a banana, your brain will remember that it is a kind of fruit that is yellow and healthy to eat. But, your brain might also remember other things that are associated with bananas, like monkeys, tropical places, or your favorite smoothie recipe.
All of these memories are connected in your brain, like a web or a spider web. When you see or hear something that reminds you of one of these memories, your brain can quickly "pop up" the other memories that are connected to it.
So, if you see a monkey at the zoo, you might suddenly remember bananas and your favorite smoothie recipe, even if you weren't thinking about those things before. This is what associative memory does - it helps your brain remember lots of things all at once, by connecting them together in a big book full of pages and pictures.