I have another question, when I set all the things up for a run, such as the Minecraft window for obs and the livesplit timer, if I start recording I have to click on the timer to activate it, but in this way it automatically pauses the game. Am I doing something wrong?

What do you mean pause?

the pause screen, with "return to game", "quit" and stuff like that

Turn on global hotkeys in the settings for livesplit. This makes it so you can control livesplit without clicking it.

It shouldn't pause the game that way

it pauses cause minecraft isnt focused

OBS and livesplit is very straight forward to setup. I would launch OBS, configure the settings for recording, and then I would add only 2 sources. A window capture source to capture the livesplit timer, and a game capture source to captutre minecraft. Once you have that setup and positioned the way you want it in OBS, I would then launch livesplit and turn on auto splitter or add start/split and reset global hotkeys. I use the auto splitter myself. The autosplitter automatically starts the timer when the world is loaded, and makes the splits for you when entering the nether, etc. Hope this helps.