How to add OAuth resource to Fusion Application OAuth Client ?

Summary:

Dear Experts,

I hope this message finds you well.
I am trying to implement single sign-on from Visual Builder Studio to an external REST API,
and I would like to achieve user identification in this process.

I am referring to the following URL:
https://www.ateam-oracle.com/how-to-integrate-external-services-into-fusion-application-visual-builder-vbs-pages-aka-fa-application-extensions

However, when I accessed IAM to check the OAuth configuration for Oracle Applications Cloud (Fusion),
I found that the Edit button was greyed out, so I could not edit the OAuth configuration.
The role FA_GSI_Administrator is already assigned.

Could anyone please advise me on how to update this setting?