How to play Heroes of Might and Magic III online via Hamachi?

I have a router at home that distributes Wi-Fi throughout the apartment. There was a long-standing problem – I couldn't connect with half of the players, but as it turned out, all the problems can be solved. The most common problem is the built-in firewall in the router. You need to configure it, and there's also something called DMZ (demilitarized zone).