how do i monitor a "remote" vcenter environment?

Hello All,

Solarwind newbie here and am currently using the evauluation version of Solarwinds VMAN. 

I feel like this is such a simple thing I want to do but I'm just lost. I have an idea based on reading documentation but it still isn't that clear to me.

Currently I have Orion installed in a Server 2019 VM with SQL Express. I am able to import our main production vCenter into Orion without any issues because there is connectivity between them.

I want to now be able to monitor several other vCenter deployments that are not directly reachable from the Orion server. I believe I need to make my Orion server open to the Internet over port 1778, install an "Additional Polling Engine (APE)" in the remote site and configure it to communicate with the main Orion server via the IP/DNS name via Internet? I read that there is no additional license cost to install an APE used for VMAN. 

Am I missing anything here?

Thanks in advance.