The retrieval process consists of three stages. The first stage retrieves small chunks from multiple documents to create a document filter using their metadat. This filter is then applied in the second stage to extract relevant large chunks, essentially sections of documents, which further refines our search parameters. Finally, using both the document and large chunk filters, the third stage retrieves the most pertinent medium-sized chunks of information to be passed to the Language Model, ensuring a focused and relevant response to your query.