Need help port forwarding

Does anybody have teamviewer that can help me? I got my own server yesterday with software from here that does it for me. It worked and we were having fun until it stopped working. Turns out it wont port forward for me again even if I close and redownload the software. I have no clue ow to port forward and the guides dont help me because they dont say anything about if something doesnt work and the ipconfig part in the cmd window doesnt work. If anybody knows software that will do it for me automatically that would b even better.