DIAGNOSIS The interface changed. Port forwarding is now under "NAT Forwarding," not the old "Forwarding" or "Virtual Server" label some older TP-Link models used.
FIX Log into the admin page. Go to Advanced > NAT Forwarding > Virtual Servers. Click "Add." You'll need the internal IP address of the device (like your game console or PC), the specific port numbers (internal and external), and the protocol (TCP, UDP, or Both). Save and it should take effect immediately.
IF THAT DIDN'T WORK Make sure the device you're forwarding to has a static IP address reserved on your local network. Go to Advanced > Network > DHCP Server > Address Reservation to lock it down. If the IP changes, the port forward breaks.
HEADS UP Double-check that your computer's local firewall (Windows Defender, etc.) isn't blocking the incoming connection even after the router forwards it. Also, your ISP might block common server ports (like for web hosting); you can't forward those.