Hello @chamnabyun.
If you have an account on one of the shared host servers (Tommy, Johnny, Ricky) then you can't access SSH for security reasons: https://wiki.helionet.org/faq#can-i-use-ssh
However if you have a VPS server then you can easily have access to SSH:
Login on https://heliohost.org/login/ with your account's username and password.
Click on "Connect to SSH on your VPS." (our just click here: https://heliohost.org/dashboard/ssh/).
On that page you'll have access to your VPS IP address, SSH service connection port and your username (your password is the same as your HelioHost account you used to login on dashboard).
Use Putty (if your OS is Windows), Google Chrome's extension "Secure Shell" (any OS that runs Chrome) or run "ssh" on your terminal (if your OS is either Mac, Linux, BSDs etc.).
Note: I did a briefly explanation about SSH connection because I'm considering that you do know how to use it. If it isn't your case reply providing your OS and I'll post a specific step-to-step for you. Also, if you found any errors while trying to connect to a VPS using SSH, please provide as many details as possible (error message, what OS and software you're using to connect to your server etc.) so we can provide a better support for you.