You have two different commenting options in Metro Publisher: our native commenting system and Facebook comments.
Metro Publisher Comments
The Metro Publisher comments feature can be activated and configured in your site-wide content settings: Content Settings
Facebook Comments
For Facebook comments, you will need a Facebook App ID which you can then enter in the appropriate field within our Facebook integration. Please follow the instructions here: Facebook Settings & Pixels
We have a help document for troubleshooting the most common issues when readers log into Facebook via the comments feature on your site here: Facebook Errors for Readers When Logging in via Comments
Comments