It is my first time using the livesplit tool for anything and although i managed to set it up after reading the guide here/watching some tutorials, what doesn't work for me is the part where it should be going from one segment to another on it's own (e.g in colosseum from wave 1.a to wave 1.b or wave 2 to wave 3 etc). I can also press the hotkey to split it by myself but is that something i am expected to be doing everytime? Because it will be inaccurate since it isn't guaranteed i will be able to press it everytime at the exact same moment (also in a video tutorial i watched it seems to be happening on it's own). Is there a setting i am missing to do this?

The autosplitter has a separate configuration (Edit Splits > Settings button); you can get splits from hksplitmaker which has autosplit triggers for all splits pre-made.

i did download the Colo 1 w/ Autosplit Waves from hksplitmaker which i assume is the correct thing. Then i opened it ingame and after i go through the entrance trigger point it instantly goes to Colo end and starts the timer. So during the trial the timer goes on but without counting any of the waves. Any idea what i am doing wrong? Is there some other setting i need to adjust to make this work?

You need to use a colo-specific save file, as the wave autosplits rely on the Journal entries being uncompleted for the relevant enemies. You can download a working file here, you will need to use DebugMod or a save editor to add the abilities you need. Also note that this is a 1221 save where Flukenest costs 2 notches instead of 3, so if you use flukenest make sure you're not still overcharmed when you're not supposed to be.

thanks for the help, i found some help from a discord server as well where someone did this for me because i have no idea how to use a debugmod but i understand what it needed and it is done now