I started feeding him by the portion guide from Iams, which basically suggests at his weight to feed him 1 can of dog food every day. Adjusting that for dry kibble, plus water, I've estimated that just under half a bowl of kibble plus water roughly equals the mass of a can of dog food.
He only eats once a day though, but often he spans that out through the day. Yes he does occasionally eat other things too, things we know he's not gonna have a bad reaction to anyways.
When we rescued/adopted him, he weighed 18.2 pounds. Last we recently weighed him, 21 pounds...
His formal name now is Brownie, but he's got multiple nicknames like fatass, chicken butt, cheese butt, etc LOL!
I'm just gonna drop some useful links here, as I'm still learning myself...
https://www.chewy.com/education/dog/food-and-nutrition/human-foods-dogs-can-eat
https://home-pet-care.com/human-foods-dogs-can-eat/
https://www.eatingwell.com/best-and-worst-foods-for-dogs-8682189