If the person is on either team and is alive, then using your right and left click mouse buttons, you can cycle through the different living players to hopefully find the one leaving feedback. If the player is dead or spectating, there is no way to teleport to their position. What Nesman is referring to is to go to your map's feedback page by searching the
feedback site. From there you can see a big long list of all the feedback in your map as well as the coordinates where that feedback was left. The easiest way to find where that feedback was left is to copy those coordinates into Hammer's "Go To Coordinates..." option under the "View" menu. If you want to find this feedback in TF2 without the help of Hammer, you'll need to use "cl_showpos 1" in console and use that to try and manually find where the feedback was left.