CircleCI's dynamic configuration is a powerful tool that can be used in various ways to dynamically generate configuration when a pipeline is triggered.
For more information on this feature please refer to CircleCI's documentation.
Each use case of dynamic config is separated by branch. Each use cases structure may be different but the basic concept is there is a config.yaml file that contains the setup workflow. A continued.yaml which contains the continued workflow(s) may exist in the repo or it may be generated in some fashion.