To create a subdomain, go to the Websites section and click on Manage next to the website in question. Then, search for Subdomains on the left, and click on it:

In the section Create a New Subdomain, enter a name for your new subdomain and select if you want to create a custom folder (directory) for it.

It's usually recommended to keep a default directory for your subdomains

Finally, click on Create:

HOW TO INSTALL SSL CERTIFICATE

 Go to Security then, select SSL and click on the Domain Status And Click Install

HOW TO CREATE FTP ACCOUNTS

Go to Files and select FTP Accounts then Change the path same path which is created in the Subdomain

Enter the details Username and Password