in x10's great tutorial:
https://community.x10hosting.com/threads/the-how-to-get-your-own-domain-for-free-tk.171405/
I'm trying to point my new .tk domain (kaotica.tk) at my new x10 site kaotica.x10.mx
<snip>
write your x10hosting url in the url box only everything before 10x
Select use DNS...