To start using Sitefinity you must download it from Sitefinity website and run the installer. Sitefinity installs and opens the Sitefinity Project Manager, which you use to start creating your project. When you start using Sitefinity for the first time you must complete the initial license installation procedure.
IMPORTANT: If you are upgrading to Sitefinity 6.0 all domain names must be explicitly registered with the license in order to turn off Trial messages on the frontend. Sitefinity sub-domains are free for all license holders, but must also be registered. To register your domains, you must send to email@example.com a list that includes all primary domains (e.g. mywebsite.com) and all sub-domains (e.g. www.mywebsite.com, test.mywebsite.com, qa.test.mywebsite.com).