This repository has samples that demonstrate various aspects of the AWS Mobile SDK for Unity, you can get the SDK source on Github (https://github.com/aws/aws-sdk-net)
The example project failed for me because all our stuff is set up in EU West 1 which, along with all the other necessary settings, is set up in the AWSPrefab (AmazonInitializer script). This wasn't being read in in by SaveManager, nor AmazonSecurityTokenServiceConfig, instead they incorrectly just defaulted to US East 1. With these small configuration changes, all now works as expected (perfectly ;) ).
The example project failed for me because all our stuff is set up in EU West 1 which, along with all the other necessary settings, is set up in the AWSPrefab (AmazonInitializer script). This wasn't being read in in by SaveManager, nor AmazonSecurityTokenServiceConfig, instead they incorrectly just defaulted to US East 1. With these small configuration changes, all now works as expected (perfectly ;) ).