DNS

I have a domain with Zoho and hosting through another provider. I don't want my www.domain.com to point to the zoho login. I added a name server in the Admin for my hosting, but I'm curious to know what are the two name servers: ns25.domaincontrol.com and ns26.domaincontrol.com why can I not delete them due to the fact that it says 'international.' Do you have a simple domain configuration guide? I'm finding the Admin Panel very unfriendly for users.

Thanks!