Port Forwarding describes the process of making your server visible to outside networks. In order for your server to communicate with a client, it needs to define a port, a number that's used within your network to identify a hosted service. This port can then be monitored by your network gateway (usually your router).
As the individual method may differ depending on the vendor of your gateway, we cannot give too detailed of an answer but port forwarding should usually be listed as a setting in your router's security options. Simply forward the ports 40 (HTTP) and 443 (SSL) to host LiquidMS.
TBA