Either be good at a certain game or follow my instructions.

First of all for speedrunning on pc you want to have Live Split and OBS

First of all for speedrunning on Ios or android you want to have screen recording on

For xbox and switch, switch idk, but with xbox you can use the in game capture thingy or you can go and buy a capture card

After all of that you want to start the timer when the run starts and record simple and then post to youtube and submit the link and stuff pog yay your a speedrunner now