Where can I find the PHP file for oauth_customer.php?
$callbackUrl = "http://yourhost/oauth_customer.php";
Am I supposed to leave these at these defaults?
$adminAuthorizationUrl = 'http://magentohost/oauth/authorize';
$accessTokenRequestUrl = 'http://magentohost/oauth/token';
$apiUrl = 'http://magentohost/api/rest';
$consumerKey = 'yourconsumerkey';
$consumerSecret = 'yourconsumersecret';
If you want to use REST API please follow this steps ...
this is for SOAP but same as for REST API.
https://bmagento.wordpress.com/2015/04/03/how-to-create-soap-api-in-magento/