A Records are used to point a website name, e.g. www.nwdemo.co.uk to an IP address, e.g. 126.96.36.199. You could use these to point direct a subdomain to a server of your own.
First login to your control panel.
Scroll down to the ‘Domains’ section and select ‘Zone Editor’
Select the ‘Manage’ option
Next to the record you wish to alter, click ‘Edit’
Enter the new IP and click ‘Save Record’
Warning: Be very careful if editing the top A Record which directs your raw domain to an IP address, as other records refer to this via CNAME and MX records.