Enter the network name, password and click "Create".

Step 2: Ask your friends to join the network
Send your friends the name of the Radmin VPN network and the password to join to this network.

Step 3: Run Hearts of Iron IV

Step 4: Add the game to the firewall exceptions
You need to add rules to the firewall. Open Radmin VPN -> System -> Firewall Exceptions and add "hoi4.exe" to the exceptions.

Step: 5 Host the game
Go to the main menu Hearts of Iron IV and click "Multiplayer".

Click "Host" button.

In the window that appears, fill in the server information: name, password, tags and description. Click "Host" button.

Game client setup

Step 1: Install Radmin VPN and connect to the network
Download and install Radmin VPN. In the main Radmin VPN window, click "Join Network". Enter the Network Name and Password and click "Join". 

Make sure you and your friends are on the same network.

Step 2: Run Hearts of Iron IV

Step 3: Add Rules to the Firewall
You need to add rules to the firewall. Open Radmin VPN -> System -> Firewall Exceptions and add "hoi4.exe" to the exceptions.

Step 4: Join the game
Go to the main menu Hearts of Iron IV and click "Multiplayer".

Click "Refresh LAN" button.

Select server and click "Join" button.

If there are no available servers in the list, click "Connect to Server ID" button and enter the Server ID to join the game.

Now you can enjoy the game with your friends.