You are just fine. Unfortunately the proces for downloading One Care is not explained well. If you have the trial installed open it and select "Subacribe". When asked for a Live ID enter the Live ID and password used to purchase your subscription and One Care will activate. If you don't have the trial installed you can download it here then follow the above instructions to activate -
http://onecare.live.com/standard/en-us/install/install.htm
Jim - MVP Windows Live - Forum Moderator - Live One Care - Live Mesh