First, make sure you have an account registered. By registered you should have gone through the registration process and received an email to confirm your account. That goes to the email you registered with. If it's not in your inbox, check your spam.

Second, once your account has been registered, make sure you are logged in and you can post here. If it prompts for a username, enter the one you used to register, not something else.

If you can't find your registered account, or you can't find the post you made, it means these instructions were not followed.