Set up a VPS to function as a RelayServer. See this link for the Requirements, and this link for more details and instructions.
Go to 08 RelayServer Utils -> 11 Email DNS Records
in Script-server. As per the provided instructions, enter your domain name, RelayServer IP address, and requisite passwords.
Go to your admin email inbox, and use the email generated from Step 2 to add/edit the DNS records at your domain name provider.
Go to 06 My Network -> 14 Set Up Hosted VPN
in Script-server. Read the provided instructions and fill out the required fields. It will take around 12-15 minutes for the installation process to complete.
Test Email - See this link for details.
The following video provides a step-by-step walkthrough, starting at the 15:35 mark: