Callback setting in Sample Postman Collection

I am trying to run the sample Postman script described here:

https://developer.okta.com/docs/reference/api/oidc/#authorize

For the authorize endpoint, I do not know what to set for the callback. Per standard OIDC, I assume I need to set the same callback in the authorization request as is in the OKTA application, right?

I saw one post describing the use of the Postman Interceptor, but I am still unclear.

Do I have to have another web app running at the same time to display the log in screen?

One site suggested using https://oauth.pstmn.io/v1/browser-callback, but that did not work.

What should the callback be set to???

Thanks for any help

Also, for {{url}}/oauth2/v1/introspect, why does the collection set the user id and password to clientId and client secret? I see the id and secret are neede, but why are they put in the user id and pwd headers?

@kenshine Hi, please check the doc here for the callback setup.
To sign users in, your application redirects the browser to an Okta-hosted sign-in page. Okta then redirects back to your application with information about the user.
For /introspect, you can refer the request parameters in the API doc.
https://developer.okta.com/docs/reference/api/oidc/#introspect
It includes the instruction of client_id and client_secret.