I think your understanding on ports is wrong. You have to port-forward.
You have to go into your router settings, go to something like ‘port forwarding’, then create a new service.
If you don’t know how to access your router or your PC’s IP, then go to Command Prompt and type ipconfig.
You are looking for IPv4 Address (which is your PC IP), and Default Gateway (which is your router IP).
Enter the number for Default Gateway into your browser. You should now be on your router’s page and it will ask for login info. (The login info is router/ISP specific so just Google it).
Once logged in, find something to do with ‘port forwarding’, then create a new ‘service’.
In this service, you enter the IPv4 Address from earlier.
Then for the port range, do 7777-7777. As for type, select Both (TCP/UDP).
Save and enable everything.
Alternatively, just Google {your router name} port forward, you should find some material.
As long as you don’t have some firewall blocking anything, people should be able to connect to your server.