How to do NAT on AWS

I’m making SIP calls using asterisk and my virtual machine is located on AWS but I’m having NAT issues and would like to know if anyone knows how to do NAT to SIP on AWS. I believe that my voip calls are not transporting media because of the NAT that is not correctly converting my public and private Ips. If anyone knows how to do this on AWS I would be grateful!

It would help if you post your configuration here. We also run a lot of asterisk servers from aws without any problems.