If your new account with Blacknight has been setup you will have received login information in the welcome email. You can use the details provided in this email to log in to your Control Panel and upload your files with your FTP details.
cp.blacknighthosting.com - Here's how to get your FTP details
cp.blacknight.com - Click here to get started
You might need to make sure the appropriate subscription is selected in the Subscription drop down menu first if you have multiple subscriptions (cp.blacknight.com only)