DNS / Nameservers

Ok, so my dad needed to buy a .es domain, obviously not from the usual UK company he gets em from. The problem is, he is using url forwarding, and it just forwards him to his webspace address (unprofessional ofc)

I told him he needs to update his dns + nameserver stuff, and so did the company, but to be fair, he has no idea what he's doing there, and I'm not so sure either.

Googling didn't really help, so anyone know what theyre doing with this? say hosting is a randomhost.com/content, and wants www.domain.com to _be_ that and not forward to it (I know what I mean).

Yeah, confusing but please help :).