The comprehensive guide outlines the process of creating a custom connector using the Airbyte Connector Development Kit (CDK), beginning with setting up the environment and running the CDK Generator. It progresses through creating and implementing the Airbyte Spec, understanding the Airbyte Protocol, and implementing essential functions like Check and Discover. The guide details defining the output schema for a stream, implementing Read, and configuring the AirbyteCatalog, before moving on to containerizing the custom connector. It also covers adding the connector to the Airbyte UI and setting up synchronization with the new connector, culminating in viewing the replicated data.