Configure server for Internet access

Hello,

I have Virtualhere server installed on Oprangepi PC Plus and it works fine inside my home network. The problem comes when I am at work or somewhere else. Client on my laptop doesn't see server. I looked into posted articles and couldn't fine anything related to possible configuration of router/switch or anything which can guide me thru configuration process to get server visible outside my local network.
It very possible that I have missed something. I will appreciate if you can post here manuals or links on the manuals which describe how to proper configure server to get an access over the Internet.

Thanks