Not working.. when i press F1 i'm not invisible... they see me
This tool only works when you are the host of the match. This tool contains a force hoster. If you can't become the host, check if your NAT type is Open and it also requires a good internet connection. If your NAT type is not at Open, you will to do some port forwarding to get it to Open.
I downloaded it and sometimes it works. After playing with people, I cannot become the host sometimes.
Is it related to what it says "turn off the invisibility when a match is over (A must)"?
You need to start the tool before looking for a match. The tool will then force host. Make sure that you have a very good internet connection and that your NAT type is Open. Players may not join right away but they will eventually. Once your host, you can use F1 to activate cheat.