Setting up AWS IAM Identity Center as SAML IdP for a Synology NAS

So, as the title states, I'm trying to set up AWS IAM Identity Center as SAML IdP for a Synology NAS (DSM 7.2). I uploaded IAM metadata to the NAS. But now I do not know where can I find application metadata (requested by AWS IC) about:

• Application ACS URL
• Application SAML audience

On the Synology client configuration, there's anything about that. Moreover, I do not know where can I find attribute mappings.

Any help is really appreciated