I do not no how to do something. When people submit a second run, there first run disappears. How can I turn this off?

If its faster, it gets obsoleted, the run still appears on the runners profile if you check "Show Obsolete Runs". You don't turn this off

What about the leaderboard?

It'll show there too if you turn the "Obsoleted Runs" variable from "Hidden" to "Shown"

Thanks for the help!