glad to help
first you need to set up the name servers at co.cc. the x10 name servers are s1.x10hosting.com and s2.x10hosting.com.
from there you need to log into cpanel. and go to the addon domains
type in the co.cc domain that you registered.
then click add domain.
lastly chedck it by typing in that domain into the adress bar. it should then take you to a blank page giving a index of the domain
and that is how it is done