Using the extension manager of Joomla! Administrator:
Once installed, access to edit through the Module Manager administration (extensions -> module manager -> administrator):
Click in Missing Metadata to edit, and display the configuration screen. Select publish and cpanel position, then Save & Close:
You can see if you access to the control panel of Joomla! administrator:
By default shows the last 5 articles, categories and menus, in which we need to write the Meta Description and/or the Meta Keywords.
The number of results you want to display on the module (for example: 5, 10, 15, 20, etc).
Tip: if you choose the number 0 will show all results.
You can choose between displaying the order recently added first, or recently modified first.
Title: shows the titles of the articles, categories and menus, which lack the meta description and/or the meta keys. Clicking on the title, you access the item edit (articles, categories and menus).
Status: indicates the status of the item, if published, unpublished, deleted and archived.
Created: indicates the created date.
Yes: indicates that you have forgotten to write it.
No: indicates it is written, and thus we have not forgotten us.
Yes: indicates that you have forgotten to write them.
No: indicates that they are written, and therefore you have not forgotten.
(Note: if both values are "no" result isn't displayed in the module, as it indicates that we have not forgotten to write).