s3: update some wording in the text

Author: max-moser

docs/operate/customize/file-uploads/s3.md

@@ -11,14 +11,14 @@ InvenioRDM provides seamless integration with S3-compatible object storage syste
     This section assumes you chose S3 when bootstrapping the instance.
 
 !!! warning "License compatibility"
-    The MinIO Object Store is licensed under Affero General Public License Version 3 (AGPLv3), see the [compliance page](https://min.io/compliance). When using MinIO, make sure that your instance's license is compliant.
+    The MinIO Object Store is licensed under Affero General Public License Version 3 ([AGPLv3](https://spdx.org/licenses/AGPL-3.0.html)), see the [compliance page](https://min.io/compliance). When using MinIO, make sure that your instance's license is compliant.
 
 After having setup your MinIO application, you can review the settings below.
 
 ### Bucket and data location
-A default bucket (`default`) is created automatically in your MinIO container. This bucket will be used as the default files' location for your InvenioRDM instance.
+A default bucket (`default`) is created automatically in your MinIO container. This bucket will be used as the default files' location for your InvenioRDM instance if you choose `s3` as file storage during project initialization.
 
-If you want to change the bucket name, open a shell window and type `pipenv run invenio files location s3-default s3://new-bucket --default`. You will also need to manually create the new bucket in minio or your S3 storage system. The new bucket will only be used for new records or drafts (existing drafts and records will use `default`).
+If you want to change the bucket name, open a shell window and type `pipenv run invenio files location s3-default s3://new-bucket --default`. You will also need to manually create the new bucket in MinIO or your S3 storage system. The new bucket will only be used for new records or drafts (existing drafts and records will use `default`).
 
 ### Credentials
 The last step is to set your credentials so your instance can authenticate against the S3 container.
@@ -29,13 +29,13 @@ By default, the `ROOT_USER` and the `ROOT_USER_PASSWORD` of MinIO are "CHANGE_ME
 - In the `docker-services.yaml` file change the `MINIO_ROOT_USER` and `MINIO_ROOT_PASSWORD` values.
 - Update the credentials:
     - You should be using environment variables to inject secrets. Define `INVENIO_S3_ACCESS_KEY_ID` for the user and `INVENIO_S3_SECRET_ACCESS_KEY` for the password.
-    - If you are developing locally, you can change your `invenio.cfg` and set the user to `S3_ACCESS_KEY_ID` and the password to `S3_SECRET_ACCESS_KEY`.
+    - If you are developing locally, you can change your `invenio.cfg` and set the value of `S3_ACCESS_KEY_ID` to the desired username and the value of `S3_SECRET_ACCESS_KEY` to the password.
 - Start your services: `invenio-cli services start`.
 
 It's done! Ready to roll!
 
 ## Amazon S3
-If you're using Amazon S3, you'll want to provide the endpoint url and set the region if you're not using us-east-1 (the default) like
+If you're using Amazon S3, you'll want to provide the endpoint URL and set the region (if you're not using the default of `us-east-1`):
 
 ```
 S3_ENDPOINT_URL='https://s3.us-west-2.amazonaws.com/'