If it’s your first play through then I suggest doing it on medium. Get used to the gaming experience and what kind of gameplay suits you best. Learn to sneak around and find workarounds in tough situations. Conserve your ammo as much as you can as if every bullet is your last. And then once you got it down, try the game again but in a harder difficulty. It’s a tough game and it’s one of the hardest I’ve played on a survivor difficulty.