New cat, need advice.

So, my boyfriend and I adopted this cat. He’s around 2 years old and came from a hoarder house that was surrounded by other cats. So, socially he has no problem. But we’ve been noticing he will eat WHATEVER (i assume it’s from being in a hoarder house and the neglect he had). I’m wondering though if anyone has advice on how to teach him what is cat food and what he can’t eat. I don’t want him to end up eating something that genuinely hurts him.

Another odd thing, but I just assume it’s part of his quirky personality that he has, is that he will meow VERY LOUDLY when he walks around the house. We’ve had him for about 3 weeks now so I’m wondering if it’s just him getting used to the house?

Let me know any thoughts that any of you have, anything is appreciated of course. 🫶