Hello,
Thanks for your question. If you're trying to park a domain for your add-on domain, you can use the re-direct option in the cPanel, or you can use the parked domains option (also in the cPanel under domains). If you use the Parked Domains option, you have to add the domain name you're trying to park, then click on Manage Re-direction for that domain in order to designate where you want the parked domain to re-direct to.
I hope this helps to answer your question! Please let us know if you require any further assistance.
Regards,
Arnel C.