A portal administrator will send you an activation email when you are assigned a license for 2c8 Apps. Click the link in the email to activate your account. When the account is activated you can use it to log into the product you have a license for, and for 2c8 Portal.
You need to activate your account within 24 hours from receiving the activation email. If it has been more than 24 hours you need to ask your portal administrator to send you another activation email.