In both the private & public port add 6346. And for ip, just complete the last no. of your internal ip.

And "click Enter near the bottom of the screen to save your changes."

You will need to re-start LW for the changes to take effect. It does depend on device. Some devices require rebooting. Some require rebooting of both device & computer & some rebooting the computer. So if you don't get showed that option, it should be ok. If in doubt reboot the computer. If the whole process did't work, then it's most likely in the initial step of setting up a static ip which btw is the most important step.