Im trying to practice just the chamber19-escap03 splits and wanna keep times on them, I tried whitelisting but I dont know what map names I should be using? I assumed the names that source uses but those arent working, any advice? i could just be using it completely wrong, if there's a tutorial somewhere on this I'd appreciate it.

the easiest way is probably just to time demos, so you'd set your speedrun_save to 19 and then time the 19, e00, e01, and e02 demos that get saved with the demo timer. if you want splits its probably best just to make a separate splits file with only those chambers.

or if you want to do each chamber separately theres a guide for that here: https://www.speedrun.com/portal/guide/4bb0d