> For the complete documentation index, see [llms.txt](https://v2.dataos.info/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://v2.dataos.info/build/v1/understand/overview.md).

# Overview

Understand is the first stage of a build, and it answers one question: **is this the right data?** Before you write a model, you find out what you already have, whether it is trustworthy, and what is missing. Building blind is how you ship a model on top of stale or wrong data and discover it weeks later.

Understand is reconnaissance. It comes before the Extract, Load, Productize pattern, not inside it. You leave this stage knowing exactly which sources to use and whether you need to [Move](/build/v1/move/overview.md) anything in first.

## What you do here

Three tasks, in the order you reach for them:

* [**Connect sources**](/build/v1/understand/connect-sources.md): register an authenticated connection to the source system, so DataOS can reach it without moving data.
* [**Scan metadata**](/build/v1/understand/scan-metadata.md): when a source has no metadata in DataOS yet, scan it so its tables, columns, lineage, and usage become discoverable.
* [**Explore data**](/build/v1/understand/explore-data.md): inspect the metadata and the actual values. Browse datasets and lineage in the catalog, then query samples in Workbench.

```mermaid
flowchart LR
    C[Connect sources] --> S{Metadata in<br/>DataOS yet?}
    S -->|no| SC[Scan metadata]
    S -->|yes| E[Explore data]
    SC --> E
    E --> D{Right data?}
    D -->|yes, and reachable| P[Productize]
    D -->|yes, but not reachable| M[Move it in first]
    D -->|no| E

    style C fill:#FAEEDA,stroke:#854F0B,color:#633806
    style SC fill:#FAEEDA,stroke:#854F0B,color:#633806
    style E fill:#FAEEDA,stroke:#854F0B,color:#633806
    style P fill:#E1F5EE,stroke:#0F6E56,color:#085041
    style M fill:#E6F1FB,stroke:#185FA5,color:#0C447C
```

## What you decide

By the end of Understand you can answer:

* **What exists?** The schemas, columns, owners, and tags of the sources you might use.
* **Can I trust it?** Lineage, and recent usage.
* **Does it fit?** Whether sample values support the use case, confirmed by querying.
* **What is missing?** Any data you still need to bring in.

If the data exists and your engine can already reach it, go straight to [Productize](/build/v1/productize/overview.md). If it exists but lives somewhere your engine cannot read, [Move](/build/v1/move/overview.md) it in first. If it does not exist, better to find out now than later.

Start with [Connect sources](/build/v1/understand/connect-sources.md).


---

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