> For the complete documentation index, see [llms.txt](https://docs.papers.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.papers.ai/getting-started/core-concepts.md).

# Core concepts

Papers AI works a bit differently from most writing tools. This page explains the ideas that people coming from Word, Google Docs, Overleaf, Jupyter, Cursor, or RStudio usually ask about first.

If you haven't opened the app yet, read [Workspace tour](/getting-started/workspace-tour.md) first. That page covers where things live on screen. This page covers how the pieces fit together underneath.

## Where your project is saved and who can see it

{% hint style="info" %}
The first time you open Papers AI without an account, you land directly in a temporary starter project so you can look around before signing up. When you create your own project, you can choose **Temporary** too, alongside saving it to your device or the cloud. See [Create or open your first project](/getting-started/create-or-open-your-first-project.md).
{% endhint %}

These are two separate questions with two separate answers. Don't confuse them: a project's storage location and its access level are independent.

{% columns %}
{% column %}

### Where it's saved

* **Temporary**: stored only in your browser, with no device folder behind it. Quick to start, but you can lose it if you clear your browser's cache or site data.
* **Local**: the project lives in a folder on your device. It isn't accessible from other devices and can't be shared until you save it to the cloud.
* **Cloud**: the project is stored on Papers AI's servers. It's accessible from any device you sign into, and it can be shared. Saving to the cloud requires an account, so you'll be asked to sign up if you haven't already.
  {% endcolumn %}

{% column %}

### Who can see it

* **Private**: only you can see and edit it. This is the default for every new project, and the only option for temporary and local projects.
* **Shared**: you've invited one or more collaborators, who can view or edit depending on their role. Only cloud projects can be shared.
  {% endcolumn %}
  {% endcolumns %}

A cloud project can be shared or completely private. Temporary and local projects are always private, simply because nobody else can reach them. That's a side effect of storage location, not a separate access setting.

Since a temporary project only exists in your browser, Papers AI prompts you to save it somewhere more permanent (your device or the cloud) whenever you navigate away from it. See [Managing your projects](/managing-projects-and-files/managing-your-projects.md).

## Projects and files

A project is the container. Files live inside it. A project usually mixes file types. A typical one might hold a `.docx` draft, a `.csv` dataset, a `.bib` bibliography, and a `.kanban` board. Papers AI doesn't separate files by type in the explorer; the folder structure is yours.

## Which editor opens for each file type

Papers AI picks the editor by file extension. A `.docx` opens in the Word-style editor, a `.md` file opens in the prose editor, a `.csv` opens in the data viewer, an `.ipynb` opens in the notebook editor. A few file types (`.pptx`, `.key`, and other presentation formats) aren't supported yet; they can live in your project, but Papers AI can't open or edit them. See [Supported file types](/getting-started/supported-file-types.md) for the full list.

## Using AI

The AI sits in the right sidebar. It can see your whole project: every file, not just the one you have open. It can also propose edits to your files; those changes go through a review step before they land, so you can check them the way you'd review a pull request.

It can help you with more than writing: summarizing a dataset, explaining a compile error, drafting citations, or restructuring a rough note are all things it can do. See [Using AI](/using-ai/using-ai.md).

## Sharing

A project is private to you until you choose to share it. If the project is temporary or saved to a local folder, sharing it moves it to the cloud first. For a local-folder project, further changes won't sync back to the folder on your device.

## Next steps

* [Quickstart](/getting-started/quickstart.md)
* [Workspace tour](/getting-started/workspace-tour.md)
* [Create or open your first project](/getting-started/create-or-open-your-first-project.md)
* [Share a project and manage access](/collaborating/share-a-project-and-manage-access.md)
* [Using AI](/using-ai/using-ai.md)