I am trying to set up a Named Credential so that I can make callouts from a Visualforce controller to an external web app using Oauth 2.x. The web application is called Procore. I'm not sure how to configure the Authentication Provider and Connected App (if the latter is needed).
1) For the Authentication Provider, should I choose Salesforce or Open ID Connect as the provider type?
2a) If I choose Salesforce, what is the URL suffix supposed to be?
2b) Also, this page says I need to set up a Connected App first. Is this really necessary since I'm just doing a callout to an external app? What should the Callback URL be for this connected app - a Salesforce URL or a Procore URL? https://help.salesforce.com/HTViewHelpDoc?id=sso_provider_sfdc.htm&language=en_US#sso_provider_sfdc
3) If I choose Open ID Connect, what is the URL suffix supposed to be? And since this requires the key and secret from Procore, what is the Redirect URI that I supply to Procore to get the key and secret?