How can I implement OAuth 2.0 (3LO) in my Web API application?

[Godson Ihemere]

I need to make some Jira REST calls in my web API application. But I have encountered difficulties around creating authentication using Oauth 2.0 according to documentation below:

https://developer.atlassian.com/cloud/jira/service-desk/oauth-2-authorization-code-grants-3lo-for-apps/

I need help on how I can call the step 1 of the above documentation in postman and subsequently, in my code to obtain the authorization code without going through a browser to paste this link below, as I am working with a backend web API application.

https://auth.atlassian.com/authorize? audience=api.atlassian.com& client_id=YOUR_CLIENT_ID& scope=REQUESTED_SCOPE_ONE%20REQUESTED_SCOPE_TWO& redirect_uri=https://YOUR_APP_CALLBACK_URL& state=YOUR_USER_BOUND_VALUE& response_type=code& prompt=consent

I hope to get suggestions as this has been a blocker for me for days. Thanks.