Assuming that the domain name is 'kickapps.com' and the sub-domain is 'affiliate', what you need is to get a record in the DNS zone file as follows :
Code:
affiliate 14400 IN CNAME kickapps.com.
Note that there is a trailing ' . ' at the end of the domain name. And, do increment the serial number in the zone file.
You can edit the DNS zone file via SSH if you have 'root' shell access. The file will be located at /var/named/kickapps.com.db
OR
You can do it directly (preferred) via WHM by using the option 'Edit a DNS zone file' as mentioned in the earlier post.
If you do not have root access to the server or any option in your control panel (only if your host provides some custom control panel) then you will have to contact their support to get the CNAME done.