How can I get code without browser

I need help. I’m new to Okta. I can already get the session token follow this article. But still unable to get code using session token in postman. It’s get the ‘"cookies are required’". And I paste the url to the browser, it’s back to the login page. I thins the only reason may be I’m setting the wrong value with state and nonce. But how can I get this value? can’t find how to get the two values.

div id=“okta-sign-in” class=“auth-container main-container unsupported-message-container” style=“display:none”>

Cookies are required

Cookies are disabled on your browser. Please enable Cookies and refresh this page.