Provide doc refs for understanding ASW credentials.

Author: pp-mo

docs/src/further_topics/s3_io.rst

@@ -97,8 +97,12 @@ S3 bucket **onto** -- e.g.
 
 Setup AWS credentials
 ~~~~~~~~~~~~~~~~~~~~~
-Provide S3 access credentials in an AWS credentials file, as described in
-`this account <https://github.com/s3fs-fuse/s3fs-fuse/blob/master/README.md#examples>`_.
+Provide S3 access credentials in an AWS credentials file, as described
+`here in the the s3-fuse documentation <https://github.com/s3fs-fuse/s3fs-fuse/blob/master/README.md#examples>`_.
+
+There is a general introduction to AWS credentials
+`here in the AWS documentation <https://docs.aws.amazon.com/cli/latest/userguide/getting-started-quickstart.html>`_
+which should explain what you need here.
 
 
 Before use (before each Python invocation)