After logging in visit the Meta manager in the CMS

Select missing and you will see all the pages that are missing their SEO tags.

Click the link button to visit a page that you need to edit SEO tags for.

The page will open in a new tab allowing you to quickly jump back to see what the next page that needs editing.

Click the Meta link on the admin bar at the bottom of the browser window.

A modal popup appears showing all the SEO details including;

• Title tag
• Meta Description
• Meta Keywords
• OG image
• H1, H2 and H3 tags used

This also shows the URL of the page being viewed and where the data will be stored.

Type or copy and paste the relevant fields. 
The OG image will either show the standard default image for the website or if the content you are viewing has an image attached to it then that image will be given.
To change the OG image you must Browse the media browser to find a relevant image to go with this page of content.

Click save once you have entered all the relevant details.

Do this for every page of your website.

It is always a good idea to create the Meta data when you create any new piece of content so that you do not have to do a lot of catching up, this also helps when posting pages to social media as this information will be used by the social media channels to display image, title, etc.