Please follow the instructions given in the opening post. The opening post has a link where you will get a unique BTC address to send payment to. Once the BTC payment has a 1 confirmation, you can revisit the link and you will then fill out a form which will allow you to apply the copper membership to your account.
Here is the link to the opening post for your convenience. https://bitcointalk.org/index.php?topic=2385104.0
Here is the link to get your unique BTC address. https://bitcointalk.org/index.php?action=credit;promote