I somehow can't figure out how to get a timer to get on my streams but I don't have a laptop and use an Xbox so if I do a stream on mixer with no timer does it count?

I am wanting to try some Xbox one runs but am unsure how to do it without a laptop seeing as how that's how you control most integrated timers I'm wondering if I stream with mixer and save the videos and have a camera pointing at a timer on my phone does that count? And how do I submit it if it does

I'm very new and am a big metal slug x player and want to get in some runs but am unsure how to upload a time and if this site accepts mixer streams if I save them and how to do that any help appreciated greatly