Mekhoo's Ultimate Tunes

So I’ve recently started to play Forza Horizon 2 and have already gotten pretty far into the game. I have already gotten 2 top 500 places on the speed cameras using my custom tuned Ultima GTR and I want to find out how to upload the tune I used so others can have a chance to place higher or just go as fast as possible. Also I would like to make it easier for people to find them and I don’t know how to put them out there so I came here. I also have quite a few other cars that are tuned better than any of the top downloads I tried.