Missing Client secret for OAuth2 implementation

I have a rails app currently up and running and i want to implement oauth2 for active campaign. I have been searching the docs and developer portal of active campaign and i still haven’t found the client id and client secret to make an oauth2 client for my app.
Some suggested to make apps in app studio and then the app will give client secret, but it didnt. Its confusing.

Anyone have already implemented oauth2 in their app in any language do answer!