Visit the router admin page at 192.168.1.1
Login with username
From the menu at the top of the page, select Firewall and click "Yes" to confirm.
From the menu on the left, select Port Forwarding.
Configure the new rule.
- Select your computer in the first dropdown.
- Select Custom Ports in the second dropdown.
TCPand the desired port.
- Click Add.
Try to make sure to clean up old rules when you're done with them.