# Understand what you built

The quickstart created a reusable path from a source document to a verifiable answer. Four resources and capabilities made that path work.

| Resource or capability | What it does |
| --- | --- |
| Catalog file | Keeps the imported PDF at a stable location in the workspace |
| Knowledge base | Processes the document and makes its content retrievable |
| Chat model | Generates an answer from the context retrieved from the knowledge base |
| Source reference | Connects the answer to the supporting passage in the original document |

## Catalog provides the source

The PDF was imported once and stored in a Catalog volume. The knowledge base refers to that managed file, so you do not need to upload a separate copy each time you use it.

Catalog also gives the source a stable path. When you add more documents or build another knowledge base, you can select existing files from the same object hierarchy.

## The knowledge base prepares the document for retrieval

Adding the PDF starts knowledge-base processing. A file is ready for questions only after **Processing Status** becomes **Completed**.

The knowledge base is reusable. You can continue asking questions about the same paper, add more supported data sources, or connect the knowledge base to an agent.

## The model answers with retrieved context

The chat model generates the response, while the knowledge base supplies relevant content from the PDF. Model availability depends on the workspace, and model or processing operations can consume Credit.

## References make the answer verifiable

A plausible answer is not enough. Opening the reference and comparing the cited passage with the response confirms whether the source supports the claims.

In the quickstart, the answer is complete only when the same passage supports **81%**, **pyflakes**, and **pep8**. Apply the same check to your own documents before relying on a generated answer.

Continue to [Where to go next](https://omnifabric.cloudsigma.com/docs/get-started/where-to-go-next.html.md) to build on these resources.