# Getting Started (/docs/guide/getting-started)



## What Is Thoughtree [#what-is-thoughtree]

Thoughtree is a native mind mapping app that can open assets (`.itmz` files) from the now-discontinued iThoughtsX. It runs on macOS, iPhone, and iPad.

You can open and edit maps you previously created in iThoughtsX, or create new maps in Thoughtree's own save format, `.ttree`.

## Installation [#installation]

Thoughtree is currently distributed through TestFlight.

1. Open the TestFlight invitation link sent by the developer.
2. Install the "TestFlight" app from the App Store, if you haven't already.
3. Install Thoughtree from within the TestFlight app.

Thoughtree runs on macOS 13 or later and iOS 16 or later.

## Creating a New Map [#creating-a-new-map]

**On macOS**, choose **File > New Map** (`⌘N`) from the menu bar to open a new map window.

**On iOS**, tap the "+" button on the document browser screen to create a new map.

A new map starts out with a single topic called the "Central Topic."

## Typing Your First Topic [#typing-your-first-topic]

Double-click the Central Topic (tap it on iOS) to edit its title. Type your text and confirm it to set the topic's title.

From there, you can add more topics with the toolbar's "New Child Topic" and "New Sibling Topic" buttons, or with the `Tab` (child topic) and `Return` (sibling topic) keys on macOS. See [Topic Basics](/docs/guide/topics) for the full set of operations.

## Saving [#saving]

Thoughtree's standard save format is `.ttree`. Newly created maps are always saved as `.ttree`.

If you open an `.itmz` file, it is never overwritten. Saving creates a new `.ttree` file instead (Thoughtree does not export back to `.itmz`).