Installing the plugin(s) is same as any other Go plugins. Please follow the GoCD documentation on installing plugins.
Builds of the plugins are available through Github releases
The plugins use the default credential provider chain used by the AWS SDK
AWS_SECRET_ACCESS_KEY environment variables can also be set from pipelines / GoCD environments, and if set those will be used to get the credentials.
AWS_USE_IAM_ROLE is set to true, the instance profile credentials are used.
AWS_REGION environment variable will have to be set in pipeline / GoCD environment / agent / server if not already set.