Generative linguistics is like a game of building with blocks. First, we have some basic blocks called "phonemes" which are the sounds that make up words. Then, we use those blocks to create bigger blocks called "morphemes" which are chunks of language that have a meaning.
With morphemes, we can start building even bigger blocks by combining them in different ways to create "phrases" and "sentences."
Generative linguistics is like a set of rules for how we can play with these blocks to create different structures. These rules tell us things like what order we can put words in, what kinds of words can go together, and what sounds are allowed in different parts of a word.
So, just like with blocks, we can create lots of different things by following these rules and putting the pieces together in different ways. And just like with blocks, there are some really complex things we can build once we have a good understanding of these rules!