You can connect to the server via FTP using cPanel >> File manager or using any 3rd party FTP clients. Connecting to your account via FTP depends on which FTP client you use. However, all of the clients will require the same basic information to connect.
Your FTP client will have an option, or will prompt you for the following information when you wish to connect.
Hostname: "ftp.your domain"
Username: "your account name"
Password: "your account password"
Port: 21
Please omit the quotes when entering the information into the FTP client. Your account name/password are the same as the ones you use to access the control panel.