Please i am a begginer in terms of speedrunning and i would like to know how to actually do it i dont want to use out of bounds glitches or any form of cheat ! i just want to run the game normally as fast as i can while recording it with the splits times on livesplit but i get an error message :this game version is only partially supported.Auto start and splitting are not available so i am kind lost ! if someone can explain me how to use them properly and in a way that i can use the auto start splitting and if i could see the timers while i am playing comparing times with me or another one it would be awesome !

You seem to want to run No Major Glitches. You're running on version 1.2 most likely. Consider down-patching to 1.1 to get the autosplitter fully operational. The Discord has more information and resources. Consider joining it.

ok thanks i did join the discord and i am currently trying to downpatch to 1.1 and i am stucked to the dotnet process i dont know how to install the dotnet part so nothing is happening :( (also will i have to use the thing to prevent me to use slopeboost with that version in order to have a valid run ?)

slopeboost is patched out in 1.1 so you don't have to do anything. i'm not sure which dotnet version is needed, if the patcher shows which version is missing and doesn't automatically install (it's supposed to though), just search for "dotnetfx installer version XX" on google or your preferred search engine.