If you have purchased a domain from Accuwebhosting.com then you need to contact us via a support ticket to get the credentials of your domain controlpanel. We will instruct you on how to edit the DNS record for your domain.
If you want to use your own server DNS then you will need to register and set the nameserver with the ns1 and ns2 of your domain with the IP Address of your server. Please refer to Accuweb > set nameserver for this.
In case, you want to directly modify the DNS record from your domain then you can keep using the domain registrar default nameserver.