Builder is one of the Creational Design Patterns.
Picture having to assemble tiny lego pieces into what looks like a house. There are several different ways of grouping them into various representations.
A basic house will have a door, zero or more windows, and a roof with surrounding walls. Some may even have a garage, and some have a swimming pool. We’d wish for the process to be simpler and flexible to accommodate changes.
A step-by-step assembly of the lego pieces at your disposal forms the essence of the Builder pattern.
If you want to learn more, here’s the link to a full article.