go to realm settings user profile tab and create user attributes (they are used in plugin code)

go to clients/(client used for login)/client scopes/add client scope

and create client scopes

choose client type to be saml (it is oidc by default)

setup URLs (localhost is a placeholder for phplist application domain)

after saving client, go to Keys and export client certificate data to use it from applicationside

go to identity providers and create saml2 provider