As super user how can I give access to end user (SAML authentication)

If you are the account admin, you will see an option on the right side of the 'My Apps' page to manage the realm.

If you have a platform or enterprise level account you will see the directory tab.

Here is a good resource from the Quick Base University on this, and a screen shot.

https://university.quickbase.com/series/account-administration/account-administration