I wanna do a dark fight scene outside at night
How would I do that
Because my camera doesn't do well with just darkness
So how would I set up lighting or whatever for that
Without knowing what you have it comes down to what you can get. There's no single solution to this problem. Even knowing what you have there's no single solution to the problem.
What lights can you get with batteries, how high can you safely mount them, and how long will they last? Can you shoot somewhere with power? How many extensions cords can you run and how many lights can you get? Don't do this if you don't know how to determine how many lights you can run on one circuit.
You have to light your actors AND your background. This is tricky. Be prepared to spend a lot of time relighting. You are going to end up changing lights with almost every camera move.
Lighting is a pretty complex topic. You're better off searching YouTube for "Outdoor video night lighting tutorial" on this topic.
It's arguably better to just shoot with sun an do aggressive day for night grading.
If you film on a cloudy day and then grade it Day for Night, you won't have any obvious shadows caused by the sun. Other tips would be to try not to get the sky in the shot (that can ruin the effect), add sound effects to sell the fact that it is night time (crickets, etc), bracket the scene with other hints that it is night time (i.e. show setting sun before the fight scene happens or at least show that it is dark outside already), and make adjustments to the Day for Night Effect to make it look real (in other words, just don't drop the effect on but really tweak just right).
Did you not cover these and more tips in a fantastic Tutorial on your channel?
I would reccomend dslr guide's "tips for filming in the dark". He basically reccomends making the background pretty bright, and having a small light on the talent(s) faces. If you live in a city with lots of streetlights and other bright lights at night, this might be easier.
I've never had good experience with day for night effects, but then again, we're talking about my word against FilmSensei's.
If you need it to look absolutely professional, and you don't have the time to light the scene, I would reccomend trying to find a way to not have the fight scene occur during nightime, unless its' abbbsolutely necesary.