You can install DCE with or without composer.

With composer

Just require DCE on cli:

$ composer req t3/dce:"^2.0"

When composer is done you need to enable the extension in the extension manager.

Without composer

You can also fetch DCE from TER and install it the old-fashioned way.

DCE in extension manager of TYPO3 CMS


You need to enable the extension in Extension Manager with or without composer in use! Or use CLI tools for that.

DCE provides no further options here.