You received the FTP access data in the email from hosttech that was sent to you when you placed your order.
You can re-download the access data sheet in your myhosttech customer center under “Servercenter” in the settings of your product.
How to change the username or password is explained in the FAQ entry How do I change the FTP password? explained.
The FTP user at Confixx is always webXXX (eg web123) and cannot be changed.