docs: Extend s3 docs

Signed-off-by: Julius Knorr <[email protected]>

docs/services/s3.md

@@ -1,5 +1,13 @@
 # S3 / Object storage
 
+S3 can be easily tested with the included container running Minio. This is a self-hosted S3-compatible object storage server.
+
+Start the container using the following command:
+
+```bash
+docker compose up -d minio
+```
+
 ## Primary object storage
 
 Primary object storage can be enabled by setting the `PRIMARY=minio` environment variable either in your `.env` file or in `docker-compose.yml` for individual containers.
@@ -8,6 +16,26 @@ Primary object storage can be enabled by setting the `PRIMARY=minio` environment
 docker compose up nextcloud minio
 ```
 
+## External object storage
+
+External storage can be configured in the Nextcloud admin settings. This is an example configuration for the `nc-external` bucket, buckets will be autocreated so you can name any bucket you like:
+
+- Bucket: `nc-external`
+- Authentication: `Access Key`
+- Hostname: `minio`
+- Port: `9001`
+- Enable SSL: `No`
+- Enable Path Style: `Yes`
+- Legacy (v2) Authentication: `Yes`
+- Access Key: `nextcloud`
+- Secret Key: `nextcloud`
+
+## Accessing Minio
+
+Minio can be accessed via the browser at <http://minio.local> with the following credentials:
+
+- Username: `nextcloud`
+- Password: `nextcloud`
 
 ## Using mc command line