[docs] Rough outline for brownfield docs

docs/constants/navigation.js

@@ -412,7 +412,7 @@ const general = [
         makePage('accounts/working-together.mdx'),
         makePage('accounts/sso.mdx'),
       ]),
-      makeSection('Bare React Native', [
+      makeSection('Existing React Native apps', [
         makePage('bare/overview.mdx'),
         makePage('bare/installing-expo-modules.mdx'),
         makePage('bare/using-expo-cli.mdx'),
@@ -422,6 +422,10 @@ const general = [
         makePage('bare/error-recovery.mdx'),
         makePage('bare/upgrade.mdx'),
       ]),
+      makeSection('Existing Native apps', [
+        makePage('brownfield/overview.mdx'),
+        makePage('brownfield/installing-expo-modules.mdx'),
+      ]),
     ],
     { expanded: true }
   ),

docs/pages/brownfield/installing-expo-modules.mdx

@@ -0,0 +1,52 @@
+---
+title: Install Expo modules
+description: Learn how to prepare your existing native project to install and use Expo modules and the module API.
+---
+
+import InstallSection from '~/components/plugins/InstallSection';
+import { DiffBlock } from '~/ui/components/Snippet';
+import { YesIcon, NoIcon } from '~/ui/components/DocIcons';
+import { Collapsible } from '~/ui/components/Collapsible';
+import Step from '~/components/Step';
+
+## Prerequisites
+
+You should have a native project with React Native installed and configured to render a root view.
+
+## Install Expo modules
+
+First, add the `expo` package to your project. Ensure you are using a version of the `expo` package that is compatible with the React Native version in your project. [Learn more](/versions/latest/#each-expo-sdk-version-depends-on-a-react-native-version).
+
+<Terminal cmdCopy="npm install expo" />
+
+### iOS
+
+<Step label="1">
+  Next thing goes here
+</Step>
+
+<Step label="2">
+  Next thing goes here again
+</Step>
+
+<Step label="3">
+  And more if needed
+</Step>
+
+### Android
+
+<Step label="1">
+  Next thing goes here but for Android this time
+</Step>
+
+<Step label="2">
+  Next thing goes here again
+</Step>
+
+<Step label="3">
+  And more if needed
+</Step>
+
+## Limitations
+
+Here we list limitations.

docs/pages/brownfield/overview.mdx

@@ -0,0 +1,41 @@
+---
+title: Integrating Expo tools into existing native apps
+sidebar_title: Overview
+hideTOC: true
+description: An overview of how you can integrate Expo tools into existing native apps ("brownfield" apps).
+---
+
+import { BoxLink } from '~/ui/components/BoxLink';
+import { Terminal } from '~/ui/components/Snippet';
+import { DEMI, CODE } from '~/ui/components/Text';
+
+If you already have a native app for Android and/or iOS and want to learn how to use Expo and React Native in your project, perhaps on a single screen or feature to start, this guide is for you. This type of app is commonly referred to as a "brownfield" app in the React Native ecosystem (as opposed to "greenfield" apps, which are created from scratch using Expo and React Native).
+
+## Compatibility
+
+Expo is primarily built with greenfield apps in mind — not all Expo tools and services are compatible with existing native projects.
+
+| Tool/Service                                        | Supports brownfield? |
+| --------------------------------------------------- | -------------------- |
+| [Expo SDK](/versions/latest/)                       | Yes                  |
+| [Expo Modules API](/modules/overview/)              | Yes                  |
+| [Expo Router](/router/introduction/)                | No                   |
+| [Expo CLI](/more/expo-cli/)                         | No                   |
+| [Expo Dev Client](/versions/latest/sdk/dev-client/) | No                   |
+| [EAS Build](/build/introduction/)                   | Yes                  |
+| [EAS Submit](/submit/introduction/)                 | Yes                  |
+| [EAS Update](/eas-update/introduction/)             | No                   |
+
+## Next steps
+
+<BoxLink
+  title="Integrating your first React Native view"
+  description="Learn how to add a React Native root view to your existing native app"
+  href="<TODO>"
+/>
+
+<BoxLink
+  title="Install Expo modules"
+  description="Install the Expo Modules API and use it to add existing Expo modules or write your own modules"
+  href="/brownfield/installing-expo-modules"
+/>