So I want to try and do a run, do I just record on OBS then edit the video to have a timer and then if there are any issues the mod will verify the time? Or is there a specific timing software I should install? Edit: I should probably add that I'll be speedrunning Minecraft Java.
If you’re using OBS to record your time you can use a timer program like LiveSplit or WSplit and the run that along with the game. At that point you can use OBS to capture both the game and the timer into a single scene for recoding/streaming.
If you run games on PC (and I assume by the name that "Minecraft Java" is a PC game), you can record the game in OBS while also recording a timer at the same time. For the timer program it is recommended to install and use LiveSplit.