“In which folder I just need to paste this code in .htaccess file? One is in the main folder?”
Yes, where your subdomain dot mydomain dot com root folder is.
“Path to suite directory how should I write?”
On cpanel, the DocumentRoot is usually something like this:
<VirtualHost *:80>
DocumentRoot /home/cpanelusername/subdomaindotmydomaindotcom/public
<Directory /home/cpanelusername/subdomaindotmydomaindotcom/public>
AllowOverride All
Order Allow,Deny
Allow from All
</Directory>
</VirtualHost>