It is available and you'd find it very easily on the webpage if you looked around a little bit

for full setup: click on resources on speedrun.com/REPO -> download the file under "splits" -> open livesplit (the program you need to have installed to your pc already) -> right click the window -> "open splits" -> find the livesplit file you just downloaded from here -> once loaded, right click the window -> "edit splits" -> next to "Autostart, split, and Load Removal", if you see the button that says "Activate", click on it to activate it, in which case the button should now read "Deactivate" (the action that it would take if you clicked on it again) which is the status you want it set to. -> "OK"

in your livesplit layout menu, be sure your timer is set to "current timing method" OR "game time" and not "real time"

this is the same process for multiple other games with an autosplitter

congratulations you can now speedrun REPO