I am trying to make it so that livesplit tracks my ingame time, i am playing on minecraft 1.12.2

Are you talking about a load remover/autosplitter? If so, you'll need to check with the Minecraft community for the game you're running and see if they have one. I checked a few of the games in the series and it looks like some of them have one, but idk which game you're running exactly. If you need help setting it up, anyone in the community should be able to assist you with it.