The main TYPO3 extension manager interface is shown in the following screenshot, and is accessed by clicking on Ext Manager on the main menu.

This view is grouped by the category, but we can change the grouping using the Group by option at the top of the page.

The Show options change the information displayed in the table of extensions. By default, we have the details view, which displays the following:

There are three different installed statuses: Installed, Not Installed, and Required.The installed status is a green circle with a minus symbol within; we can click on the symbol if we wish to remove the extension. The not installed status is a grey symbol with a plus sign within; we can install that particular extension by clicking on the symbol. The required symbol is the letters Rq in red. This symbol does not do anything as the extensions that are classed as required...