How to create a VPN tunnel through a 3G router with a gray IP?

Question

VPN

Hello everyone, a question from a person far from the IT-sphere.
The initial data are as follows:
1) a computer with Internet access via a gray IP;
2) 3G router Novacom GNS-UR5i with a gray IP SIM card;
3) An industrial PLC that will be connected to the router via LAN via the Ethernet port that needs to be accessed.
Task: On the computer, through the Java plugin in the browser, you need to monitor the status of all controller menus.
What is the question: by what means can the whole thing be connected to a person who does not understand administration, but has a desire to understand?

Answer 1

whitewash the IP in the third paragraph
on the router in paragraph 3 port forwarding on the PLC
OR
VPN on the VPS and connections from all three (two) to this VPS

Answer 2

With such inputs, you can’t do without an intermediate node with a public ip. AWS provides a free VDS with minimal xp and white ip, enough to deploy a pptp or l2tp server. It remains only to raise the tunnels and configure the routing.