1. control panel -> network and internet -> network and sharing center -> change adapter settings (on the left side of the screen)

2. right click radmin vpn and select properties

3. select internet protocol version 4 (TCP/IPv4) and select properties

4. set IP address to start with 192.168, the next two numbers do not matter as long as they are within the 20s (make sure it's not the same address as the people you want to play with)

5. leave subnet mask at its default value

6. completely delete everything in the default gateway and DNS fields

7. select advanced at the bottom

8. set interface metric to 1 (you may have to uncheck the box next to automatic metric)

9. select ok on every window that is open (ignore the warnings windows gives you)

10. allow radmin vpn and civ 6 through both your firewall and antivirus

11. (only if you can't get it to work after doing the above steps) port forward the ports that civ 6 uses (only the host would need to do this)

12. open radmin vpn and connect to the same network as the people you want to play with

13. open civ 6, and either host or join a lan game

Note, steps 1-9 need to be redone every time you restart your computer

if it still doesn't work, try having someone else host it. i cannot host games for some reason, but i can still join them