Setup Open Graph and Twitter Cards globally

Go to SEO, Social Networks, and click Enable this feature (if it’s not the case).

In Facebook tab, check Enable OG data.

You can also set a default image (in case of one of your post, page, post type, doesn’t have one).

Do the same for Twitter and don’t forget to click Save changes.

Manage Facebook OG and Twitter Cards individually

Edit a post, page or post type.

In SEO metabox, Social tab, you can define:

• a Facebook Title (post title if empty)
  
• a Facebook Description (excerpt if empty or begining of your content)
  
• a Facebook Thumbnail (post thumbnail if empty)
  
• a Twitter Title (post title if empty)
  
• a Twitter Description (excerpt if empty or begining of your content)
  
• a Twitter Thumbnail (post thumbnail if empty)
  

Don’t forget to save your post.