Alright so.. I use windows recorder, and it doesn't show multiple windows.. that being said- I can't show the timer. Do I need to have the timer or does it matter?

It depends on the game. You should ask the moderators for the game you're speedrunning.

I also would use OBS for all recording. It’s pretty much the defacto standard for deciding/streaming runs. It will allow you to capture as many Windows as you want in your layout.

Well, the thing is, I can't use OBS.. for some reason, it just won't allow me to. :/

What do you mean by "won't allow"? did your OBS having a frame drops or technical issues or something? About the timer ones, it's on the moderator sides. If the mods said to show the timer, then you must show the timer. If not, then you can just time your runs separately (by running the livesplit in the background or using frame timer [if you upload it on youtube]).

I asked the moderator, they said they time the run. But OBS won't download on my PC