I know this sounds a little dumb but I am new to this. Can I submit a run that is like 100th place or something?
If people could only submit WR runs there'd be many many less runs on the site
As long as your runs qualified (not breaking the game rules and such) on a leaderboard, then yes. Also, there's no need to worry about "Xth places" submission. If you think that you get a good time runs, then submit it to the leaderboard. As simple as that.
You speedrun for yourself and your own growth. Forget about the world record holders. One day, you'll be on top!
Expanding on what Riekelt said, personally I find a combination of "competing against yourself" and "competing against the leaderboard" to be a good way to think of it.
Like, play your game. Just complete it as fast as you can. If you got a 55:29? Sweet, you're close to getting a sub 55. So submit the run, don't even care where it is on the board, and keep pushing yourself to get into the 54 mark.
Okay, so now you got a 54:47? Have a glance at the leaderboard. Wow, you're 7th, still a bit away from the top, but 6th place is only 54:39. You can do it! That is your aim now.
Awesome, some time has passed and now you own a 53:35. This puts you at 4th place? Maybe now is a good time to look at the WR holder's runs, and 2nd and 3rd place. Now you're competing against yourself, 3rd place and with an eye on the WR.
I dunno, that's kind of how I think of it. Just keep getting better :) but yes, submit that 100th place run OP!
This isn't SpeedDemosArchives (praise be). As long as your run shows a sincere attempt to complete the category it's submitted for speedily (and frankly, even if it doesn't in some cases) and follows all the rules of that category, that's all you need.