please clear this spiderweb for me

I hope this is a right section - I just couldn't find the better one.
I'm totally confused and hoping someone with knowledge can point me what am I supposed to do. So
My domain is registered with 007names
I added subdomain on my hosting server like blog.mysite.com
I want to use this subdomain with Godaddy blogcast.
GoDaddy tells me I need to change the A record and point it to the right IP address.
Where do I change it - registar or hosting?
I had a look at registar options however can't find anything with A record in it. I can change DNS but that's all.

Do I change it for my domain or subdomain?
Honestly - I'm completely lost

 

the A record should be changed in the Hosting.

 

Thanks,
which part of Cpanel you find it in?

 

you can use everydns.net

Point your nameserver to everydns and add:
blog.mysite.com A the IP Address

 

Thanks ayaw for help.
I registed there and tried to do iy however it's saying the following
Make sure that your domain points to ns1.everydns.net, ns2.everydns.net, ns3.everydns.net, and ns4.everydns.net in your registrar's whois database. Without that, none of your records will resolve properly.

Is it talking about the main domain - if yes - won't I loose the website if I do it?
And if it's talking about subdomain - where does it have DNS settings?

 

you can set everydns to point your main domain to your current host
and point your subdomain to another

just get your current host IP and add it
yourdomain.com A Your current host IP
blog.yourdomain.com A GoDaddy IP

 

Thank you for your help. It's all done now and I hope once I publish the blog it will work

 

u're welcome mate