The Meta Open Graph Report
The meta open graph report helps by showing what meta open graph tags there are on each page.

Source URL
The url the open graph tags were found on.
og:title
The og:title tag of the page. Like regular titles, you want this to be filled in and not a duplicate of others.
og:description
The og:description of the page. Should give a good, unique, description of your page.
og:image
The og:image tag. The image that sites linking to this page should use. It should point to a good, representative, image.
og:url
The og:url tag will generally contain the same url as "Source URL"
og:type
The og:type tag contains the type of the content according to opengraph. In most cases this will be "website" or "article".
og:sitename
The og:sitename tag contains the site's name, so generally his will list the same thing in each row.
og:locale
The og:local tag contains the site's local. Again, generally this will be the same thing in each row.
og:image_alt
The og:image_alt tag holds the alt tag for the og:image image. This should be filled in.
Hint
A number of these columns are the same on every row. Once you know what the value is, you might want to hide those columns to make the screen easier to read. Click on the three dots menu at the top left, choose "Columns" and turn off any columns you don't want.