The Authress IAP contains two things:
- Infrastructure Stack Template
- Source code for authentication via a lambda/cloud function
You can already directly deploy the stack template without any additional work.
When your users end up at your website, if they are not already logged in, they will be automatically redirected to your Authress hosted login page asking them to login to gain access. Additionally, the assets in your bucket will be checked against Authress to ensure that the user has access to the exact resource they are attempting to view. This is done using Authress authorization.