Hey, so I used to speedrun celeste on an old computer, but I recently got a new one and am trying to set everything back up. I have the Autosplitter enabled in LiveSplit, however whenever I start a run it doesnt start at all and if I manually start the timer it doesnt split for levels. Any assistance?

You have to go into the autosplitter settings and add the sections where you want it to split. There's some presets for this as well.

you can find premade splits files for pretty much every category at https://www.speedrun.com/celeste/resources , those will have the settings handled for you. or if you can get your old .lss file from you old computer onto your new one, that will have all the same autosplitter settings (and also your run history and everything which you might want to keep running against lol)