Set a subdomain as parked domain

Hi
I wanna set a subdomain like blog.example.com(which is mine) to my website.
But I need one IP address(not 4 or 5) to do this.
what’s that IP address?

In your example, is example.com already hosted with us? Because if it’s using our nameservers, you don’t need to configure anything yourself (just add it through the Subdomains section). Or, if you are using your own nameservers but already have the domain with us, you can just use the same IP as your main domain.

the main domain is using other NS(example.com) in other hosting company but I wanna add sub.example.com as a parked domain to my host(which you host) so I need “one” ip address to do it

Actually, you can use nameservers on subdomains too. To do so, you will have to create NS records for your subdomain. You can create NS records and point them to ns1-4.byet.org.