Installation does not require Cinema 4D to be installed on your system. Cineware must, however, be activated by setting up a free user account. This can be done directly in Unity when using Cineware.
Unity provides an asset store at https://assetstore.unity.com/ for installing extensions. If you search for 'Cineware' there, can load this extension from the corresponding information page.
After starting Unity, you will find the Package Manager there in the Window menu. From there, all components of Cineware can be installed directly by clicking on the import button(see image below).
A dialog window will open, in which the Cineware components can be viewed and, if necessary, configured individually for import. After clicking the Import button again, the Cineware components will appear in the Project/Assets in Unity.