You have a number of issues. First you must check if the router has a vpn server function. Next you might have a issue with internet connection. This router appears to be used for celluar broadband...it can run others but it would be strange to have this router as a normal router.
If it is cellular broadband most providers do not give you actually addresses. They run carrier nat. Because of this you can not access your router from the internet. This is the port mapping issue you see talked about when people want to access a server in their house but in this case it is the ISP doing the NAT and you can not change their router.
It you get a actually routable ip on your wan port then you have a chance if the router support vpn server