1. How to activate my license?
Crusader comes with Free Trial mode which can be activated on any domain, any time. But the Free Trial will eventually expire and during the period of Free Trial you will have a watermark on your website. To activate your Crusader with your license, it is necessary to go to http://members.n-finity.org/members-area/product-management/, copy e-mail address and license key shown on that page and insert them inside of Crusader's License Management page.
2. If I deactivate my license on one website, can I use it on a different website?
Yes, absolutely, it works like that.