Choosing a hostname during CWP installation

[satechhelp]

I have 2 domain mainly for my websites. Its seems like i'm required to enter a hostname during the installation of CWP 
I just moved from shared hosting to VPS.
My question is' what is this hostname? Do i have to use one of my website domains? please help i'm new here

[satechhelp]

My Hosting provider gave me this "AFF20-NIX01" said to be my hostname but it is not FQDM.

[Samuel da cruz]

A host seria a sua identificação de servidor em url. Use um subdomínio do seu domínio principal. Exemplo servidor.seudomínio.com