As mentioned, always unlimited hay 24/7. It’s a must.
With veggies, the idea is about two times the size of your bunny’s head if the veggies were chopped. Usually when your bunny stops eating, that’s about the portion they should be eating, and then you can gauge it from there (but some bunnies overeat).
Pellets, it’s 1/4 – 1/2 a cup per 6 lbs, but we stay at 1/4 and maybe even a little less because Mr. Java gets a good variety of greens (6-7 different veggies/herbs a day).
You can feed a little fruit everyday as a treat. It’s a great way to bond with your bunny especially if you hand feed it to them, and also serves as a great training treat. Only enough to be about the size of your thumb, or less if your bunny gets poopy butt / soft poop. Bananas are a common favorite! I adore watching Java go insane when he gets the smell of a fresh banana.
It’s our favorite part of the night.
EDIT: I can’t remember if your bunny is a baby or not. I remember reading that in another one of your threads. If so, then feed less on that fruit because it’s like 1 teaspoon roughly per 2 lbs.