I purchased the Advanced Edition of AMP due to the fact this version of AMP supports SSO, according to your website. I have been unable to find a guide anywhere for enabling/setting up SSO.
Hover over it (press and hold on mobile) to get the more detailed description. AMP supports using LDAP compatible providers as an SSO provider for authentication. SSO is not a single thing, just the idea that a separate provider can be used to provide logins to different services, and you can use an LDAP server to log into AMP, as well as other services - resulting in a single point of authentication for multiple services - also called SSO. LDAP is commonly used to provide SSO.
AMPs LDAP support also allows it to use services such as Active Directory to provide SSO that way.
Support for other SSO providers such as OIDC/OAuth2 is planned but not yet available.