Hey everyone i have a serious problem when playing multiplayer games especially ubisoft every time i enter online it says that's my nat is strict and i am a complete newbie in networking and don't know what to do or how to remove it i tried going to my router's website that's http://192.168.1.254 and assigning a public ip address but it says Not assigned and no compatible device found and don't know what to do pls help 
MY Router Is Speedtouch ST510 V6

MY Router Is Speedtouch ST510 V6