Get authorization (roles, permissions) okta after authentication with OKTA saml

I have a web application that works as a SAML service provider using Okta as the identity provider. MFA active, and the authentication process working, now I need to obtain the roles and permissions configured in okta for the app, but I have found that I must create a saml assertion for this, that is not compatible with the previous configuration that I have of the authentication?

You will need to define custom attribute statements.

Once you have configured the attribute statement in Okta, you will need to update your service provider to parse the new attributes and use them to determine the user’s roles and permissions. This may require updating your SAML assertion parsing code to handle the new attributes.