NightFall to prophecies installation process

Alright so I have a nightfall character and Ive bought guild wars prophecies. So I know how to get to Lion Arch IN THE GAME. But im wondering how dose my account know that i have prophecies, what do i do in the installation process so that I my account in nightfall account has merged with the prophecies and successfully lets me into prophecies

Log into your current account; go on Options and Manage your Keys/Serials or whatever; and add the new 1 that came when you bought Prophecies to your main account.

Just to let you know you don't have to install the chapter, just do what the post above me says.

The other way to add a new key is when your on the login screen click "Create or add a new key" link that's under the password box. Then make sure you select the "Add to existing account" option (if you create a new account you can never merge the accounts) and follow the prompts to add the key to your account.

Then when you log in, click the manage account (or is it edit? options? I have no GW access right now) and select "Manage your cd-key's" (or similar".. then look at the games activated.. it should list both Prophecies and Nightfall. This will confirm that the adding of the cd-key was done correctly.