A subdomain is an address under your main domain, such as shop.example.com, app.example.com, or staging.example.com.
shop.example.com.public_html/shop is usually enough.shop.example.com, use a path like shop.example.com/public if the application files are stored in a shop.example.com folder and the web entry point is inside its public folder.Use Create Website only when Idea Comindo support has asked you to create a separate top-level website. For normal client work, use Create Sub / Addon Domain so the subdomain stays under your existing hosting account.
If the subdomain already exists and the document root needs to be changed, open a support ticket. For security, existing document root changes may be handled by support.
If you see a permission error or the subdomain limit is reached, open a support ticket from the client portal and include the main domain, the subdomain, and the document root path you want to use.