If you're transitioning from a current Clover website to the newest version of Clover Sites, it's important to note that you won't use the shared password for your previous Greenhouse when purchasing your new site. You'll want to create a brand new Clover user account, which you'll be using from now on with Clover Sites.
Clover Sites is user based so the first account you create during the purchase process is the one that will own the site. This person will be in charge of maintaining the website and handling details such as billing and contact info. You can also invite new users to help edit and maintain your website anytime from the Dashboard. When you purchase a Clover Site, you'll have to create and sign in with a new user account, even if you're already a customer with the previous version of Clover.