ok but how can I get the splitter to be right next to the game like on the speed run streams?

Hi, I'm new to speed running and I just got a Mac M1 running on MacOS Ventura 13. I have OBS to record but I need a splitter. I tried the one on the App Store but I can't find any tutorials.

I started running yesterday in Any%. How should I do? P.-S.: I didn't submit it yet but my PB is 7 mn 25 sec.

Hey, I started speedrunning today with Celeste classic; Any advice ?