diff --git a/docs/user-guides/email-providers/index.md b/docs/user-guides/email-providers/index.md
index 045a175..771b706 100644
--- a/docs/user-guides/email-providers/index.md
+++ b/docs/user-guides/email-providers/index.md
@@ -1,2 +1,9 @@
-# email-providers
+# Connecting Email Providers
 
+Open Archiver can connect to a variety of email sources to ingest and archive your emails. This section provides guides for connecting to popular email providers.
+
+Choose your provider from the list below to get started:
+
+-   [Google Workspace](./google-workspace.md)
+-   [Microsoft 365](./microsoft-365.md)
+-   [Generic IMAP Server](./imap.md)
diff --git a/docs/user-guides/installation.md b/docs/user-guides/installation.md
index f261330..6fd375b 100644
--- a/docs/user-guides/installation.md
+++ b/docs/user-guides/installation.md
@@ -49,6 +49,70 @@ By default, the Docker Compose setup uses local filesystem storage, which is per
 
 If you want to use S3-compatible object storage, change the `STORAGE_TYPE` to `s3` and fill in your S3 credentials (`STORAGE_S3_*` variables).
 
+### Using External Services
+
+For convenience, the `docker-compose.yml` file includes services for PostgreSQL, Valkey (Redis), and Meilisearch. However, you can use your own external or managed instances for these services.
+
+To do so:
+
+1.  **Update your `.env` file**: Change the host, port, and credential variables to point to your external service instances. For example, you would update `DATABASE_URL`, `REDIS_HOST`, and `MEILI_HOST`.
+2.  **Modify `docker-compose.yml`**: Remove or comment out the service definitions for `postgres`, `valkey`, and `meilisearch` from your `docker-compose.yml` file.
+
+This will configure the Open Archiver application to connect to your services instead of starting the default ones.
+
+### Environment Variable Reference
+
+Here is a complete list of environment variables available for configuration:
+
+#### Application Settings
+
+| Variable        | Description                        | Default Value |
+| --------------- | ---------------------------------- | ------------- |
+| `NODE_ENV`      | The application environment.       | `development` |
+| `PORT_BACKEND`  | The port for the backend service.  | `4000`        |
+| `PORT_FRONTEND` | The port for the frontend service. | `3000`        |
+
+#### Docker Compose Service Configuration
+
+These variables are used by `docker-compose.yml` to configure the services.
+
+| Variable            | Description                                     | Default Value                                            |
+| ------------------- | ----------------------------------------------- | -------------------------------------------------------- |
+| `POSTGRES_DB`       | The name of the PostgreSQL database.            | `open_archive`                                           |
+| `POSTGRES_USER`     | The username for the PostgreSQL database.       | `admin`                                                  |
+| `POSTGRES_PASSWORD` | The password for the PostgreSQL database.       | `password`                                               |
+| `DATABASE_URL`      | The connection URL for the PostgreSQL database. | `postgresql://admin:password@postgres:5432/open_archive` |
+| `MEILI_MASTER_KEY`  | The master key for Meilisearch.                 | `aSampleMasterKey`                                       |
+| `MEILI_HOST`        | The host for the Meilisearch service.           | `http://meilisearch:7700`                                |
+| `REDIS_HOST`        | The host for the Valkey (Redis) service.        | `valkey`                                                 |
+| `REDIS_PORT`        | The port for the Valkey (Redis) service.        | `6379`                                                   |
+| `REDIS_PASSWORD`    | The password for the Valkey (Redis) service.    | `defaultredispassword`                                   |
+| `REDIS_TLS_ENABLED` | Enable or disable TLS for Redis.                | `false`                                                  |
+
+#### Storage Settings
+
+| Variable                       | Description                                      | Default Value             |
+| ------------------------------ | ------------------------------------------------ | ------------------------- |
+| `STORAGE_TYPE`                 | The storage backend to use (`local` or `s3`).    | `local`                   |
+| `STORAGE_LOCAL_ROOT_PATH`      | The root path for local file storage.            | `/var/data/open-archiver` |
+| `STORAGE_S3_ENDPOINT`          | The endpoint for S3-compatible storage.          |                           |
+| `STORAGE_S3_BUCKET`            | The bucket name for S3-compatible storage.       |                           |
+| `STORAGE_S3_ACCESS_KEY_ID`     | The access key ID for S3-compatible storage.     |                           |
+| `STORAGE_S3_SECRET_ACCESS_KEY` | The secret access key for S3-compatible storage. |                           |
+| `STORAGE_S3_REGION`            | The region for S3-compatible storage.            |                           |
+| `STORAGE_S3_FORCE_PATH_STYLE`  | Force path-style addressing for S3.              | `false`                   |
+
+#### Security & Authentication
+
+| Variable         | Description                                         | Default Value                              |
+| ---------------- | --------------------------------------------------- | ------------------------------------------ |
+| `JWT_SECRET`     | A secret key for signing JWT tokens.                | `a-very-secret-key-that-you-should-change` |
+| `JWT_EXPIRES_IN` | The expiration time for JWT tokens.                 | `7d`                                       |
+| `ADMIN_EMAIL`    | The email for the initial admin user.               | `admin@local.com`                          |
+| `ADMIN_PASSWORD` | The password for the initial admin user.            | `a_strong_password_that_you_should_change` |
+| `SUPER_API_KEY`  | An API key with super admin privileges.             |                                            |
+| `ENCRYPTION_KEY` | A 32-byte hex string for encrypting sensitive data. |                                            |
+
 ## 3. Run the Application
 
 Once you have configured your `.env` file, you can start all the services using Docker Compose: