1.    Download FileZilla Client - free ftp program by going to http://filezilla-project.org
2.    Install the program on your Computer (Windows XP/Vista, MacOS X, Linux, etc)
3.    Open the FileZilla Client
4.    Click File > Site Manager (or press Ctrl+S)
5.    In Site Manager:

a. give your connection a name in MySites
b. enter Host: ftp.YourDomain.com
c. Servertype: FTPES – FTP over explicit TLS/SSL
d: Logintype: Normal
e: User: (by default it’s yourdomain.com, but you can change it in HELM Control Panel)
f: Password: (by default it’s the same as for your HELM Login)

6.    Click OK
7.    When you Connect make sure to accept certificate for Secure Encrypted Connection
8.    You have configured your FTP client to connect and upload your webfiles.

Source with Images:
https://community.aspnix.com/t/3160.aspx