Genkit RAG

Hello, I have been trying to connect my data to Genkit using the steps Provided in the official document.       https://firebase.google.com/docs/genkit/rag       
I'm not able  to figure out how to do this can you please help me out with this. And can you tell me how to connect our local or cloud database to the Genkit models, and what are all types of data we can connect to the models provided by the Genkit.