To submit a speedrun, use the button "Submit run" in the category you want to submit to. First, you'll need a video proof to submit a speedrun, so make sure to upload it somewhere like Youtube or elsewhere.

Submit form explained :

Category : That's the category you want to submit to, make sure it matchs with your speedrun. Players : That's the speedrun.com usernames of people who did the speedrun. Time without loads : This is "Time with loads" after you remove the loading time. Time with loads : This is the real time, you can add it if you use an external timer like LiveSplit. In-game time : That's the time showed in-game. Version : Always put the last version here (after cam update). Platform : Put the platform you're using here (PC, MAC, XBOX, etc). Date : That's when you did your speedrun, it usually correspond to the date of the video. Video link : Put the video proof link here. splits i/o : That's usefull if you use a split software like LiveSplit and wanna share the splits time. Description : You can add anything you want here, like the seed for a set seed speedrun.