Z.com WordPress can be accessed only with SFTP. (FTP and FTPS cannot access to our server.) Please access to our server by SFTP software.
You can set up two types of SFTP account (Master Account/Additional Account).
You can set up a Master Account at SFTP Master Account section of Z.com WordPress.
You can access to all the WordPress when you manage them by single control panel.
You can create an additional account from the control panel.
It can only access to the WordPress you specified.